T    K 
3?75 

N    6 

1909 

MAIN 


bO    15=! 


19O9 


»» 


RATIONAL  ELECTRICAL  CODE 
INSTALLATION  RULES 

(Except  Marine  Work) 


lioqal  Board  of  Fire  Underwriters 


RL.ECTRIC    WIRING 


AND 

ARPA.RA.TUS 


As  Recommended  by  the 
>ERWRITERS'  NATIONAL  ELECTRIC  ASSOCIATION 


SUPPLEMENT. 

For  satisfactory  work  only  approved  fittings 
should  be  used.  The  Supplement  to  the  National 
Electrical  Code,  containing  a  list  of  approved  elec- 
trical fittings,  is  designed  to  aid  wiremen  hy  show- 
ing them  in  advance  just  what  will  fce  approved 
by  the  Underwriters.  Fittings  not  listed  should 
not  be  used  without  special  approval,  which  will 
be  freely  given  on  application,  if  the  device  is 
found  to  be  reliable. 

The  Supplement  will  be  revised  semi-annually. 


19O9 

|"NATIONAL  ELECTRICAL  CODE 
INSTALLATION  RULES 

(Except  Marine  Work) 


OF  THE 


National  Board  of  Fire  Underwriter!) 

<i 

FOR 

HLrBCTRIO   \VIRIIVG 

AND 

ARRARATUS 

As  Recommended  by  the 
UNDERWRITERS'  NATIONAL  ELECTRIC  ASSOCIATION 


EDITION   OF   1909 


C.-H  -a 

The  National  Electrical  Code  was  originally 
drawn  in  1897  as  the  result  of  the  united  efforts 
of  the  various  Insurance,  Electrical,  Architectural] 
and  allied  interests  which  through  the  National! 
Conference  on  Standard  Electrical  Rules,  composed 
of  delegates  from  various  National  Associations, 
unanimously  voted  to  recommend  it  to  their 
respective  associations  for  approval  or  adoption ; 
and  is  here  presented  by  the  National  Board  of 
Fire  Underwriters  with  the  various  amendments 
and  additions  which  have  been  made  since  that 
time  by  them. 

The  following  is  a  list  of  the  Associations  com- 
posing the  National  Conference  on  Standard  Elec- 
trical Rules : — 

AMERICAN  INSTITUTE  OF  ARCHITECTS. 

AMERICAN  INSTITUTE  OF  ELECTRICAL  ENGINEERS. 

AMERICAN  SOCIETY  OF  MECHANICAL  ENGINEERS. 

AMERICAN  INSTITUTE  OF  MINING  ENGINEERS. 

AMERICAN  STREET  AND  INTERURBAN  RAILWAY  ASSO- 
CIATION. 

ASSOCIATED  FACTORY  MUTUAL  FIRE  INS.  Go's. 

ASSOCIATION  OF  EDISON  ILLUMINATING  COMPANIKS. 

INTERNATIONAL  ASSOCIATION  OF  MUNICIPAL  ELEC- 
TRICIANS. 

NATIONAL  BOARD  OF  FIRE  UNDERWRITERS.      , 

NATIONAL  ELECTRIC  LIGHT  ASSOCIATION. 

NATIONAL  ELECTRICAL  CONTRACTORS'  ASSOCIATION. 

NATIONAL  ELECTRICAL  INSPECTORS'  ASSOCIATION. 

UNDERWRITERS'  NATIONAL  ELECTRIC  ASSOCIATION. 


TO    CONTRACTORS. 


This  volume  contains  only  the  installation  rules 
under  Classes  A,  B,  C  and E,  such  as  are  required  by 
tb.e  contractor  "on  the  job,"  and  is  for  general 
distribution. 

Another  volume  is  issued  in  a  small  edition  con- 
taining requirements  for  the  construction  of  approved 
devices  and  materials  (Class  D),  and  rules  for 
Marine  Wiring  (Class  F).  This  second  volume  will 
not  be  furnished  for  general  distribution,  as  the  semi- 
annual List  of  Approved  Fittings  will  give  tb.e  con- 
tractor all  the  information  as  to  approved  devices 
which  he  may  need. 


207754 


GENERAL  PLAN 

GOVERNING  THE  ARRANGEMENT  OF 
RULES. 


CLASS  A.— STATIONS  AND  DYNAMO  ROOMS. 
Includes  Central  Stations  ;  Dynamo,  Motor  and 
Storage-Battery  Rooms;  Transformer  Sub-sta- 
tions, etc.  Rules  1  to  11. 

CLASS  B.— OUTSIDE  WORK,  all  systems  and 
voltages.  Rules  12  to  13  A . 

CLASS  C.— INSIDE  WORK  :— 

General  Rules,  all  systems  and  -voltages.    Rules  14 

to  17. 

Constant-Current  Systems.    Rules  18  to  20. 
Constant  Potential   Systems  : — 

General  Rules,  all  voltages.    Rules  21  to  23. 

Low-Potential  Systems,  550  volts  or  less.  Rules  24 
to  34. 

High. Potential  Systems,  550  to  3,500  volit.  Rules 
35  to  37. 

Extra  High  Potential  Systems,  over  3,500  volts. 
Rules  38  and  39. 

CLASS  D.-FITTINGS,  MATERIALS  AND  DE- 
TAILS OF  CONSTRUCTION,  all  systems  and 

voltages.    Rules  40  to  63. 

NOTE.— Class  D  is  omitted  from  tliis  pamphlet. 
CLASS  E.    MISCELLANEOUS.     Rules  64  to  67 
CLASS  F.    MARINE   WORK.     Rules  68  to  83. 
NOTE.— Class  F  is  omitted  from  this  pamphlet. 


GENERAL     SUGGESTIONS. 

The  following  as  well  as  the  fine  print  notes  in 
the  rules  are  simply  suggestions  and  explanations 
and  are  in  no  case  to  be  considered  by  inspection 
departments  as  mandatory. 

In  all  electric  work,  conductors,  however  well 
insulated,  should  always  be  treated  as  bare,  to  the 
end  that  under  no  conditions,  existing  or  likely  to 
exist,  can  a  ground  or  short  circuit  occur,  and 
so  that  all  leakage  from  conductor  to  conductor, 
or  between  conductor  and  ground,  may  be  reduced 
to  the  minimum. 

In  all  wiring  special  attention  should  be  paid  to 
the  mechanical  execution  of  the  work.  Careful 
and  neat  running,  connecting,  soldering,  taping  of 
conductors,  and  securing  and  attaching  of  fittings, 
are  specially  conducive  to  security  and  efficiency, 
and  are  strongly  advised. 

In  laying  out  an  installation,  except  for  constant 
current  systems,  every  reasonable  effort  should  be 
made  to  secure  distribution  centers  located  in 
easily  accessible  places,  at  which  points  the  cut- 
outs and  switches  controlling  the  several  branch 
circuits  can  be  grouped  for  convenience  and  safety 
of  operation.  The  load  should  be  divided  as  evenly 
as  possible  among  the  branches,  and  all  compli- 
cated and  unnecessary  wiring  avoided. 

The  use  of  wire-ways  for  rendering  concealed 
wiring  permanently  accessible  is  most  heartily 
endorsed  and  recommended ;  and  this  method  of 
accessible  concealed  construction  is  advised  for 
general  use. 

Architects  are  urged,  when  drawing  plans  and 
specifications,  to  make  provision  for  the  channel- 
ing and  pocketing  of  buildings  for  electric  light  or 
power  wires,  and  also  for  telephone,  district  mes- 
senger and  other  signaling  system  wiring. 


CLASS  A. 

STATIONS    AND     DYNAMO 
ROOMS. 

Includes    Central    Stations,    Dynamo,    Motor    and 
Storage-Battery   Rooms,   Transformer 

Sub-stations,    Etc. 
1.     Generators. 

a.  Must  be  located  in  a  dry  place. 

It  is  suggested  that  water-proof  covers  be  provided, 
which  may  be  used  in  case  of  emergency. 

6.  Must  never  be  placed  in  a  room  where  any 
hazardous  process  is  carried  on,  nor  in  places 
where  they  would  be  exposed  to  inflammable 
gases  or  flyings  of  combustible  materials. 

c.  Must,  when  operating  at  a  potential  in  excess 
of  550  volts,  have  their  base  frames  permanently 
and  effectively  grounded. 

Must,  when  operating  at  a  potential  of  550 
volts  or  less,  be  thoroughly  insulated  from  the 
ground  wherever  feasible.  Wooden  base  frames 
used  for  this  purpose,  and  wooden  floors  which 
are  depended  upon  for  insulation  where,  for  any 
reason,  it  is  necessary  to  omit  the  base  frames, 
must  be  kept  filled  to  prevent  absorption  of 
moisture,  and  must  be  kept  clean  and  dry. 

Where  frame  insulation  is  impracticable,  the 
Inspection  Department  having  jurisdiction  may, 
in  writing,  permit  its  omission,  in  which  case 
the  frame  must  be  permanently  and  effectively 
grounded. 

If  desired  high  potential  machines  may  be  surrounded 
by  an  insulated  platform,  made  of  wood,  mounted  on 
insulating  supports,  and  so  arranged  that  a  man  must 
always  stand  upon  it  in  order  to  touch  any  part  of  the 
machine. 


CLASS   A. — STATIONS 


1.    Generators— Continued, 

d.  Constant  potential  generators,  except  alter- 
nating current  machines  and  their  exciters,  must 
be   protected  from   excessive   current  by    safety 
fuses  or  equivalent  devices  of  approved  design. 

For  two-wire,  direct-current  generators,  single 
pole  protection  will  be  considered  as  satisfying  the 
above  rule,  provided  the  safety  device  is  located 
in  the  lead  not  connected  to  the  series  winding. 
When  supplying  three-wire  systems,  the  genera- 
tors must  be  so  arranged  that  these  protective 
devices  will  come  in  the  outside  leads. 

For  three-wire,  direct-current  generators,  a 
safety  device  must  be  placed  in  each  armature, 
direct-current  lead,  or  a  double  pole,  double  trip 
circuit  breaker  in  each  outside  generator  lead  and 
corresponding  equalizer  connection. 

e.  Must  each  be  provided  with  a  name-plate, 
giving  the  maker's  name,  the  capacity  in  volts  and 
amperes,  and  the  normal  speed  in  revolutions  per 
minute. 

/.  Terminal  blocks  when  used  on  generators 
must  be  made  of  approved  non-combustible,  non- 
absorptive,  insulating  material,  such  as  slate, 
marble  or  porcelain. 

g.  The  use  of  soft  rubber  bushings  to  protect  the 
lead  wires  coming  through  the  frames  of  genera- 
tors is  permitted,  except  when  installed  where 
oils,  grease,  oily  vapors  or  other  substances  known 
to  have  rapid  deleterious  effect  on  rubber,  are 
present  in  such  quantities  and  in  such  proximity 
with  motor  or  dynamo  as  may  cause  such  bush- 
ings to  be  liable  to  rapid  destruction.  In  such 
cases  hard  wood  properly  filled,  or  preferably 
porcelain  or  micanite  bushings  must  be  used. 

2,     Conductors, 

From  generators  to  switchboards,  rheostats  or 
other  instruments,  and  thence  to  outside  lines  : — 


AND    DYNAMO   ROOMS. 


2,    Conductors— Continued. 

a.  Must  be  in  plain  sight  or  readily  accessible. 

Wires  from  generator  to  switchboard  may,  how- 
ever, be  placed  in  a  run-way  in  the  brick  or  cement 
pier  on  which  the  generator  stands.  When  protec- 
tion against  moisture  is  necessary,  lead  covered 
cable  or  iron  conduit  must  be  used. 

6.  Must  have  an  approved  insulating  covering 
as  called  for  by  rules  in  Class  "C"  for  similar 
work,  except  that  in  central  stations,  on  exposed 
circuits,  the  wire  which  is  used  must  have  a  heavy 
braided,  non-combustible  outer  covering. 

Bus  bars  may  be  made  of  bare  metal. 

Where  a  number  of  wires  are  brought  close  to- 
gether, as  is  generally  the  case  in  dynamo  rooms, 
especially  about  the  switchboard,  they  must  be 
surrounded  with  a  tight,  non-combustible  outer 
cover. 

Flame  proofing  must  be  stripped  back  on  all 
cables  a  sufficient  amount  to  give  the  necessary 
insulation  distances  for  the  voltage  of  the  circuit 
on  which  the  cable  is  used. 

c.  Must,  where  not  in  a  conduit,  be  kept  so 
rigidly  in  place  that  they  cannot  come  in  contact. 

d.  Must  in  all  other  respects  be  installed  with 
the  same  precautions  as  required  by  rules  in  Class 
"  C  "  for  wires  carrying  a  current  of  the  same  vol- 
ume and  potential. 

e.  In  wiring  switchboards,  the  ground  detector 
voltmeter,  pilot  lights  and  potential  transformers 
must  be  connected  to  a  circuit  of  not  less  than 
No.  14  B.  &  S.  gage  wire  that  is  protected  by  an 
approved  fuse,  this  circuit  is  not  to  carry  over  660 
watts. 

For  the  protection  of  instruments  and  pilot 
lights  on  switchboards,  approved  N.  E.  Code 
Standard  Enclosed  Fuses  are  preferred,  but 
approved  enclosed  fuses  of  other  designs  of  not 
over  two  (2}  amperes  capacity,  may  be  used. 


over  iwo  (z 


10  GLASS  A. — STATIONS 

3,  Switchboards. 

a.  Must  be  so  placed  as  to  reduce  to  a  minimum 
the  danger  of  communicating  fire  to  adjacent  com- 
bustible material. 

Switchboards  must  not  be  built  up  to  the  ceil- 
ing, a  space  of  ,three  feet  being  left,  ir  possible, 
between  the  ceiling  and  the  board.  The  space 
back  of  the  board  must  be  kept  clear  of  rubbish 
and  not  used  for  storage  purposes. 

b.  Must  be  made  of  non-combustible  material  or 
of  hardwood   in  skeleton  form,  filled  to  prevent 
absorption  of  moisture. 

If  wood  is  used  all  wires  and  all  current  carry- 
ing parts  of  the  apparatus  on  the  switchboard 
must  be  separated  therefrom  by  non-combus- 
tible, non-absorptive,  insulating  material. 

c.  Must  be  accessible  from  all  sides  when  the 
connections  are  on  the  back,  but  may  be  placed 
against  a  brick  or  stone  wall  when  the  wiring  is 
entirely  on  the  face. 

If  the  wiring  is  on  the  back,  there  must  be  a 
clear  space  of  at  least  eighteen  inches  between  the 
wall  and  the  apparatus  on  the  board,  and  even  if 
the  wiring  is  entirely  on  the  face,  it  is  much  bet- 
ter to  have  the  board  set  out  from  the  wall. 

d.  Must  be  kept  free  from  moisture. 

e.  On  switchboards  the  distances  between  bare 
live  parts  of  opposite  polarity  must  be  made  as 
great  as  practicable,  and  must  not  be  less  than 
those  given  for  tablet-boards. 

4,  Resistance  Boxes  and  Equalizers, 

a.  Must  be  placed  on  a  switchboard,  or  at  a 
distance  of  at  least  one  foot  from  combustible 
material,  or  separated  therefrom  by  a  slab  or 
panel  of  non-combustible,  non-absorptive,  insulat- 
ing material  such  as  slate,  soapstone  or  marble, 
somewhat  larger  than  the  rheostat,  which  must 
be  secured  in  position  independently  of  the  rheo- 


AND   DYNAMO   BOOMS.  11 

• 

4,  Resistance  Boxes  and  Equalizers— Continued, 
stat  supports.  Bolts  for  supporting  the  rheostat 
shall  be  countersunk  at  least  1-8  inch  below  the 
surface  at  the  back  of  the  slab  and  filled.  For 
proper  mechanical  strength,  slab  should  be  of  a 
thickness  consistent  with  the  size  and  weight  of 
the  rheostat,  and  in  no  case  to  be  less  than  1-2  inch. 
If  resistance  devices  are  installed  in  rooms  where 
dust  or  combustible  flyings  would  be  liable  to  ac- 
cumulate on  them,  they  must  be  equipped  with  a 
dust-proof  face  plate. 

b.  Where  protective  resistances  are  necessary  in 
connection  with  automatic  rheostats,  incandescent 
lamps  may  be  used,  provided   that  they  do   not 
carry  or  control  the  main  current  nor  constitute 
the  regulating  resistance  of  the  device. 

When  so  used,  lamps  must  be  mounted  in  porce- 
lain receptacles  upon  non-combustible  supports, 
and  must  be  so  arranged  that  they  cannot  have 
impressed  upon  them  a  voltage  greater  than  that 
for  which  they  are  rated.  They  must  in  all  cases 
be  provided  with  a  name-plate,  which  shall  be 
permanently  attached  beside  the  porcelain  recep- 
tacle or  receptacles  and  stamped  with  the  candle- 
power  and  voltage  of  the  lamp  or  lamps  to  be 
used  in  each  receptacle. 

c.  Wherever  insulated  wire  is  used  for  connec- 
tion between  resistances  and  the  contact  plate  of 
a  rheostat,  the  insulation  must  be  u  slow  burning.1' 
For  large  field  rheostats  and  similar  resistances, 
where  the  contact  plates  are  not  mounted  upon 
them,  the  connecting  wires  may  be  run  together 
in  groups  so  arranged  that  the  maximum  differ- 
ence of  potential  between  any  two  wires  in  a  group 
shall  not  exceed  75  volts.     Each  group  of  wires 
must  either  be  mounted  on  non-combustible,  non- 
absorptive  insulators  giving  atleast  1-2  inch  separa- 
tion from  surface  wired  over,   or,   where  it    is 
necessary  to  protect  the  wires  from   mechanical 
injury  or  moisture,  be  run  in  approved  lined  con- 
duit or  equivalent. 


12  CLASS   A. — STATIONS 

5,  Lightning  Arresters. 

a.  Must  be  attached  to  each  wire  of  every  over- 
head circuit  connected  with  the  station. 

b.  Must  be  located  in  readily  accessible  places 
away  from  combustible  materials,  and  as  near  as 
practicable  to  the  point  where  the  wires  enter  the 
building. 

In  all  cases,  kinks,  coils  and  sharp  bends  in  the 
wires  between  the  arresters  and  the  outdoor  lines 
must  be  avoided  as  far  as  possible. 

c.  Must  be  connected  with  a  thoroughly  good  and 
permanent  ground  connection  by  metallic  strips  or 
wires  having  a  conductivity  not  less  than  that  of  a 
No.  6  B.  &  S.  gage  copper  wire,  which  must  be  run 
as  nearly  in  a  straight  line  as  possible  from  the 
arresters  to  the  ground  connection. 

Ground  wires  for  lightning  arresters  must  not 
be  attached  to  gas  pipes  within  the  buildings  nor 
be  run  inside  of  iron  pipes. 

d.  All  choke  coils  or  other  attachments,  inherent 
to  the  lightning  protection  equipment,  shall  have 
an  insulation  from  the  ground  or  other  conductors 
equal  at  least  to  the  insulation  demanded  at  other 
points  of  the  circuit  in  the  station. 

6,  Care  and  Attendance, 

a.  A   competent  man   must  be   kept   on   duty 
where  generators  are  operating. 

b.  Oily  waste  must  be  .kept  in  approved  waste 
cans  and  removed  daily. 

7,  Testing  of  Insulation  Resistance. 

a.  All  circuits  except  such  as  are  permanently 
grounded  in  accordance  with  No.  13  A  must  be 
provided  with  reliable  ground  detectors.  Detec- 
tors which  indicate  continuously  and  give  an 
instant  and  permanent  indication  of  a  ground  are 
preferable.  Ground  wires  from  detectors  must 
not  be  attached  to  gas  pipes  within  the  building. 


AND    DYNAMO    ROOMS.  13 

7,  Testing  of  Insulation  Resistance— Continued. 

ft.  Where  continuously  indicating  detectors  are 
not  feasible,  the  circuits  should  be  tested  at  least 
once  per  day,  and  preferably  oftener. 

8,  Motors, 

When  motors  operating  at  a  potential  in  excess  of 
550  volts  are  to  be  installed,  it  is  suggested  that  plans 
for  such  installations  should  be  submitted  to  the  In- 
spection Department  having  jurisdiction  before  any 
work  is  begun. 

a.  Must,  when  operating  at  a  potential  in  ex- 
cess of  550  volts,  have  no  exposed  live  metal 
parts,  and  have  their  base  frames  permanently 
and  effectively  grounded. 

Motors  operating  at  a  potential  of  550  volts  or 
less  must  be  thoroughly  insulated  from  the 
ground  wherever  feasible.  Wooden  base  frames 
used  for  this  purpose,  and  wooden  floors,  which 
are  depended  upon  for  insulation  where,  for  any 
reason,  it  is  necessary  to  omit  the  base  frames, 
must  be  kept  filled  to  prevent  absorption  of  moist- 
ure, and  must  be  kept  clean  and  dry.  Where 
frame  insulation  is  impracticable,  the  Inspection 
Department  having  jurisdiction  may,  in  writing, 
permit  its  omission,  in  which  case  the  frame 
must  be  permanently  and  effectively  grounded. 

If  desired,  high-potential  machines  may  be  sur- 
rounded with  an  insulated  platform  made  of  wood, 
mounted  on  insulating  supports,  and  so  arranged  that  a 
man  must  stand  upon  it  in  order  to  touch  any  part  of 
the  machine. 

6.  Motors  operating  at  a  potential  of  550  volts 
or  less  must  be  wired  with  the  same  precautions 
as  required  by  rules  in  Class  "C"  for  wires 
carrying  a  current  of  the  same  volume. 

Motors  operating  at  a  potential  between  550 
and  3,500  volts  must  be  wired  with  approved 
multiple  conductor,  metal  sheathed  cable  in  ap- 
proved unlined  metal  conduit  firmly  secured  in 


14  CLASS    A. — STATIONS 

8,    Motors— Continued. 

place.  The  metal  sheath  must  be  permanently 
and  effectively  grounded,  and  the  construction 
and  installation  of  the  conduit  must  conform 
to  rules  for  interior  conduits  (see  No.  25),  except 
that  at  outlets  approved  outlet  bushing  shall  be 
used. 

The  motor  leads  or  branch  circuits  must  be  de- 
signed to  carry  a  current  at  least  25  per  cent 
greater  than  that  for  which  the  motor  is  rated. 
Where  the  wires  under  this  rule  would  be  over- 
fused  in  order  to  provide  for  the  starting  cur- 
rent, as  in  the  case  of  many  of  the  alternating 
current  motors,  the  wires  must  be  of  such  size  as 
to  be  properly  protected  by  these  larger  fuses. 

The  insulation  of  the  several  conductors  for  high 
potential  motors,  where  leaving  the  metal  sheath 
at  outlets,  must  be  thoroughly  protected  from 
moisture  and  mechanical  injury.  This  may  be 
accomplished  by  means  of  a  pot  head  or  some 
equivalent  method.  The  conduit  must  be  sub- 
stantially bonded  to  the  metal  casings  of  all  fittings 
and  apparatus  connected  to  the  inside  high  tension 
circuit. 

Where  outside  wires  directly  enter  the  motor 
room  the  Inspection  Department  having  jurisdic- 
tion may  permit  the  wire  for  high  potential  mo- 
tors to  be  installed  according  to  the  general  rules 
for  high  potential  systems. 

c.  Each  motor  and  resistance  box  must  be  pro- 
tected by  a  cut-out  and  controlled  by  a  switch 
(see  No.  17  a),  said  switch  plainly  indicating 
whether  "on"  or  "off"  (except  as  provided  for 
electric  cranes,  see  34  A-c).  With  motors  of  one- 
fourth  horse  power  or  less,  on  circuits  where  the 
voltage  does  not  exceed  300,  No.  21  d  must  be 
complied  with,  and  single  pole  switches  may  be 
used  as  allowed  in  No.  22  c.  The  switch  and  rhe- 
ostat must  be  located  within  sight  of  the  motor, 
except  in  cases  where  special  permission  to  locate 


AND   DYNAMO    BOOMS.  15 


8,    Motors— Continued. 

them  elsewhere  is  given,  in  writing,  by  the  In- 
spection Department  having  jurisdiction. 

Where  the  circuit-breaking  device  on  the  motor- 
starting  rheostat  disconnects  all  wires  of  the  cir- 
cuit, the  switch  called  for  in  this  section  may  be 
omitted. 

Overload-release  devices  on  motor-starting  rhe- 
ostats will  not  be  considered  to  take  the  place  of 
the  cut-out  required  by  this  section  if  they  are  in- 
operative during  the  starting  of  the  motor. 

An  automatic  circuit-breaker  disconnecting  all 
wires  of  the  circuit  may,  however,  serve  as  both 
switch  and  cut-out. 

d.  Rheostats  must  be  so  installed  as  to  comply 
with  all  the  requirements  of  No.  4.     Auto  starters 
must  comply  with  requirements  of  No.  4  c. 

Auto  starters,  unless  equipped  with  tight  cas- 
ings enclosing  all  current-carrying  parts,  in  all 
wet,  dusty  or  linty  places,  must  be  enclosed  in 
dust-tight,  fireproof  cabinets.  Where  there  is  any 
liability  of  short  circuits  across  their  exposed  live 
parts  being  caused  by  accidental  contacts,  a  rail- 
ing must  be  erected  around  them. 

e.  Must  not  be  run  in  series-multiple  or  multi- 
ple-series, except  on  constant-potential  systems, 
and  then  only  by  special  permission  of  the  Inspec- 
tion Department  having  jurisdiction. 

/.  Must  be  covered  with  a  waterproof  cover 
when  not  in  use,  and,  if  deemed  necessary  by  the 
Inspection  Department  having  jurisdiction,  must 
be  enclosed  in  an  approved  case. 

Such  enclosures  must  be  readily  accessible,  dust 
proof  and  sufficiently  ventilated  to  prevent  an  ex- 
cessive rise  of  temperature.  Where  practicable  the 
sides  should  be  made  largely  of  glass,  so  that  the 
motor  may  be  always  plainly  visible. 

The  use  of  enclosed  type  motor  is  recommended 
in  dusty  places,  being  preferable  to  wooden 
boxing. 


16  CLASS   A. — STATIONS 

8,  Motors— Continued, 

g.  Must,  when  combined  with  ceiling  fans,  be 
hung  from  insulated  hooks,  or  else  there  must  be 
an  insulator  interposed  between  the  motor  and  its 
support. 

h.  Must  each  be  provided  with  a  name-plate, 
giving  the  maker's  name,  the  capacity  in  volts 
and  amperes,  and  the  normal  speed  in  revolutions 
per  minute. 

L  Terminal  blocks  when  used  on  motors  must 
be  made  of  approved  non-combustible,  non- 
absorptive,  insulating  material  such  as  slate, 
marble  or  porcelain. 

j.  Adjustable  speed  motors,  unless  of  special 
and  appropriate  design,  if  controlled  by  means  of 
field  regulation,  must  be  so  arranged  and  con- 
nected that  they  cannot  be  started  under  weakened 
field. 

9,  Railway  Power  Plants, 

a.  Each  feed  wire  before  it  leaves  the  power 
plant  must  be  protected  by  an  approved  automatic 
circuit-breaker  or  other  device,  which  will  imme- 
diately cut  off  the  current  in  case  of  an  accidental 
ground.  This  device  must  be  mounted  on  a  tire- 
proof  base,  and  in  full  view  and  reach  of  the 
attendant. 

10,  Storage  or  Primary  Batteries, 

a.  When  current  for  light  and  power  is  taken 
from  primary  or  secondary  batteries,  the   same 
general  regulations  must  be  observed  as  apply  to 
similar  apparatus  fed  from   dynamo   generators 
developing  the  same  difference  of  potential. 

b.  Storage  battery  rooms  must  be  thoroughly 
ventilated.       ; 

c.  Special  attention  is  directed  to  the  rules  for 
wiring  in  rooms  where  acid  fumes  exist  (see  No. 
24,  t  and.;). 


AND    DYNAMO    BOOMS.  17 

10,  Storage  or  Primary  Batteries— Continued. 

d.  All  secondary  batteries  must  be  mounted  on 
non-absorptive,  non-combustible  insulators,  such 
as  glass  or  thoroughly  vitrified  and  glazed  por- 
celain. 

e.  The  use  of  any  metal  liable  to  corrosion  must 
be  avoided  in  cell  connections  of  secondary  bat- 
teries. 

11,  Transformers.-- 

(See  also  Nos,  13,  13  A,  36.) 

a.  In  central  or  sub-stations  the  transformers 
must  be  so  placed  that  smoke  from  the  burning 
out  of  the  coils   or  the  boiling  over  of  the  oil 
(where  oil  filled  cases  are  used)  could  do  no  barm. 

b.  In  central  or  sub-stations  casings  of  all  trans- 
formers   must    be    permanently    and    effectively 
grounded. 

Transformers  used  exclusively  to  supply  current 
to  switchboard  instruments  need  not  be  grounded, 
provided  they  are  thoroughly  insulated. 


CLASS  B. 
OUTSIDE    WORK. 

(Light,  Power  and  Heat.     For  Signaling  Systems, 
see  Class  E.) 

ALL  SYSTEMS  AND  VOLTAGES, 

12,     Wires, 

a.  Line  wires  must  have  an  approved  weather- 
proof or  rubber  insulating  covering.     That  por- 
tion of  the  service  wires  between  the  main  cut-out 
and  switch  and  the  first  support  from  the  cut-out 
or  switch  on  outside  of  the  building  must  have  an 
approved  rubber   insulating  covering,   but  from 
the  above-mentioned  support  to  the  line,  except 
when   run   in   conduit,    may  have    an    approved 
weatherproof  insulating  covering  if  kept  free  from 
awnings,  swinging  signs,  shutters,  etc. 

b.  Must  be  so  placed  that  moisture  cannot  form 
a  cross  connection  between  them,  and  except  when 
run  in  conduit,  not  less  than  a  foot  apart,  and  not 
in  contact  with  any  substance  other  than  their 
insulating  supports.     Wooden  blocks   to   which 
insulators  are  attached  must  be  covered  over  their 
entire  surface  with  at  least  two  coats  of  water- 
proof paint. 

For  conduit  work,  wires  must  be  placed  so  as 
to  conform  to  rules  for  unlined  conduit  except 
that  conduit  system  must  be  waterproof. 

c.  Must  be  at  least  seven  feet  above  the  highest 
point  of  flat  roofs,  and  at  least  one  foot  above  the 
ridge  of  pitched  roofs  over  which  they  pass  or  to 
which  they  are  attached  and  roof  structures  must 
be  substantially  constructed. 


CLASS    B. — OUTSIDE    WORK.  19 


12,    Wires— Continued. 

(Z.   (Stricken  out.) 

e.  Must,  where  exposed  to  the  weather,  be  pro- 
vided with  petticoat  insulators  of  glass  or  porce- 
lain ;  porcelain  knobs  or  cleats  and  rubber  hooks 
will  not  be  approved.  Wires  on  the  exterior  walls 
of  buildings  must  be  supported  at  least  every  fif- 
teen feet,  the  distance  between  supports  to  be 
shortened  if  wires  are  liable  to  be  disturbed. 

Where  not  exposed  to  the  weather,  low  potential 
wires  may  be  supported  on  glass  or  porcelain 
knobs  which  will  separate  the  wires  at  least  one 
inch  from  the  surface  wired  over,  supports  to  be 
placed  at  least  every  four  an  one  half  feet. 

/.  Must  be  so  spliced  or  joined  as  to  be  both  me- 
chanically and  electrically  secure  without  solder. 
The  joints  must  then  be  soldered,  to  insure  pres- 
ervation, and  covered  with  an  insulation  equal  to 
that  on  the  conductors. 

All  joints  must  be  soldered,  unless  made  with 
some  form  of  approved  splicing  device. 

g.  Must,  where  they  enter  buildings,  have  drip 
loops  outside,  and  the  holes  through  which  the 
conductors  pass  must  be  bushed  with  iion-com- 
bustible,  non-absorptive,  insulating  tubes  slanting 
upward  toward  the  inside. 

For  low  potential  systems  the  service  wires  may 
be  brought  into  buildings  through  a  single  iron 
conduit.  The  conduit  to  be  equipped  with  an 
approved  service-head.  The  inner  end  must  ex- 
tend to  the  service  cut-out,  and  if  a  cabinet  is 
required  by  the  Code  must  properly  enter  the 
cabinet. 

h.  Electric  light  and  power  wires  must  not  be 
placed  on  the  same  cross-arm  with  telegraph, 
telephone  or  similar  wires,  and  when  placed  on 
the  same  pole  with  such  wires  the  distance 
between  the  two  inside  pins  of  each  cross-arm 
must  not  be  less  than  twenty-six  inches. 

i.  The  metallic  sheaths  to  cables  must  be  per- 
manently and  effectively  connected  to  u earth." 


20  CLASS    B. — OUTSIDE    WORK. 

12,    Wires-Continued, 
Trolley  Wires. 

j.  Must  not  be  smaller  than  No.  0  B.  &  S.  gage 
copper  or  No.  4  B.  &  S.  gage  silicon  bronze,  and 
must  readily  stand  the  strain  put  upon  them  when 
in  use. 

k.  Must  have  a  double  insulation  from  the 
ground.  In  wooden  pole  construction  the  pole 
will  be  considered  as  one  insulation. 

L  Must  be  capable  of  being  disconnected  at  the 
power  plant,  or  of  being  divided  into  sections,  so 
that  in  case  of  fire  on  the  railway  route,  the  cur- 
rent may  be  shut  off  from  the  particular  section 
and  riot  interfere  with  the  work  of  the  firemen. 
This  rule  also  applies  to  feeders. 

:n.  Must  be  safely  protected  against  accidental 
contact  where  crossed  by  other  conductors. 

Where  guard  wires  are  used  they  must  be  insu- 
lated from  the  ground  and  electrically  discon- 
nected in  sections  of  not  more  than  300  feet  in 
length. 

Ground  Return  Wires. 

n.  For  the  diminution  of  electrolytic  corrosion 
of  underground  metal  work,  ground  return  wires 
must  be  so  arranged  that  the  difference  of  poten- 
tial between  the  grounded  dynamo  terminal  and 
any  point  on  the  return  circuit  will  not  exceed 
twenty-five  volts. 

It  is  suggested  that  the  positive  pole  of  the  dynamo 
be  connected  to  the  trolley  line,  and  that  whenever 
pipes  or  other  underground  metal  work  are  found  to  be 
electrically  positive  to  the  rails  or  surrounding  earth, 
that  tbey  be  connected  by  conductors  arranged  so  as  to 
prevent  as  far  as  possible  current  flow  from  the  pipes 
into  the  ground. 


CLASS    B. — OUTSIDE    WORK.  21 

12  A,     Constant-Potential    Pole    Lines,    Over   5,000 
Volts. 

(Overhead  lines  of  this  class  unless  properly  ar- 
ranged may  increase  the  lire  loss  from  the  following 
causes:— 

Accidental  crosses  between  such  lines  and  low-po- 
tential lines  may  allow  the  high-voltage  current  to  en- 
ter buildings  over  a  large  section  of  adjoining  country. 
Moreover,  such  high-voltage  lines,  if  carried  close  to 
buildings,  hamper  the  work  of  firemen  in  case  of  lire  in 
the  building.  The  object  of  these  rules  is  so  to  direct 
this  class  of  construction  that  no  increase  in  lire  hazard 
will  result,  while  at  the  same  time  care  has  been  taken 
to  avoid  restrictions  which  would  unreasonably  impede 
progress  in  electrical  development. 

It  is  fully  understood  that  it  is  impossible  to  frame 
rules  which  will  C9ver  all  conceivable  cases  that  may 
arise  in  construction  work  of  such  an  extended  and 
varied  nature,  and  it  is  advised  that  the  Inspection 
Department  having  jurisdiction  be  freely  consulted  as 
to  any  modification  of  the  rules  in  particular  cases.) 

a.  Every  reasonable  precaution  must  be  taken 
in  arranging  routes  so  as  to  avoid  exposure  to 
contacts  with  other  electric  circuits.  On  existing 
lines,  wherfi  there  is  a  liability  to  contact,  the 
route  should  be  changed  by  mutual  agreement 
between  the  parties  in  interest  wherever  possible. 

6.  Such  lines  should  not  approach  other  pole 
lines  nearer  than  a  distance  equal  to  the  height  of 
the  taller  pole  line,  and  such  lines  should  not  be 
on  the  same  poles  with  other  wires,  except  that 
signaling  wires  used  by  the  Company  operating 
the  high-pressure  system,  and  which  do  not  enter 
property  other  than  that  owned  or  occupied  by 
such  Company,  may  be  carried  over  the  same 
poles. 

c.  Where  such  lines  must  necessarily  be  carried 
nearer  to  other  pole  lines  than  is  specified  in  Sec- 
tion 6  above,  or  where  they  must  necessarily  be 
carried  on  the  same  poles  with  other  wires,  extra 
precautions  to  reduce  the  liability  of  a  breakdown 
to  a  minimum  must  be  taken,  such  as  the  use  of 
wires  of  ample  mechanical  strength,  widely 


22  CLASS    B. — OUTSIDE    WORK. 

12  A,    Constant-Potential  Pole  Lines,  over  5,000  volts— Continued, 

spaced  cross-arms,  short  spans,  double  or  extra 
heavy  cross-arms,  extra  heavy  pins,  insulators, 
and  poles  thoroughly  supported.  If  carried  on 
the  same  poles  with  other  wires,  the  high-pressure 
wires  must  be  carried  at  least  three  feet  above  the 
other  wires. 

d.  Where  such  lines  cross  other  lines,  the  poles 
of  both  lines  must  be  of  heavy  and  substantial 
construction. 

Whenever  it  is  feasible,  end-insulator  guards 
should  be  placed  on  the  cross-arms  of  the  upper 
line.  If  the  high-pressure  wires  cross  below  the 
other  lines,  the  wires  of  the  upper  line  should  be 
dead-ended  at  each  end  of  the  span  to  double- 
grooved,  or  to  standard  transposition  insulators, 
and  the  line  completed  by  loops. 

One  of  the  following  forms  of  construction  must 
then  be  adopted : — 

1.  The  height  and  length   of  the   cross-over 

span  may  be  made  such  that  the  shortest 
distance  between  the  lower  cross-arms  of 
the  upper  line  and  any  wire  of  the  lower 
line  will  be  greater  than  the  length  of  the 
cross-over  span,  so  that  a  wire  breaking 
near  one  of  the  upper  pins  would  not  be 
long  enough  to  reach  any  wire  of  the 
lower  line.  The  high-pressure  wires 
should  preferably  be  above  the  other 
wires. 

2.  A  joint  pole  may  be  erected  at  the  crossing 

point,  the  high-pressure  wires  being  sup- 
ported on  this  pole  at  least  three  feet 
above  the  other  wires.  Mechanical 
guards  or  supports  must  then  be  pro- 
vided, so  that  in  case  of  the  breaking  of 
any  upper  wire,  it  will  be  impossible  for 
it  to  come  into  contact  with  any  of  the 
lower  wires. 


CLASS    B. — OUTSIDE    WORK.  23 


12  A,    Constant-Potential  Pole  Lines,  over  5,000  volts— Continued, 

Such  liability  of  contact  may  be  prevented 
by  the  use  of  suspension  wires,  similar  to 
those  employed  for  suspending  aerial  tele- 
phone cables,  which  will  prevent  the  high- 
pressure  wires  from  falling,  in  case  they 
break.  The  suspension  wires  should  be  sup- 
ported  on  high-potential  insulators,  should 
have  ample  mechanical  strength,  and  should 
be  carried  over  the  high  pressure  wires  for 
one  span  on  each  side  of  the  joint  pole,  or 
where  suspension  wires  are  not  desired  guard 
wires  may  be  carried  above  and  below  the 
lower  wires  for  one  span  on  each  side  of  the 
joint  pole,  and  so  spread  that  a  falling  high- 
pressure  wire  would  be  held  out  of  contact 
with  the  lower  wires./- 

Such  guard  wires  should  be  supported  on 
high-potential  insulators  or  should  be 
grounded.  When  grounded,  they  must  be  of 
such  size,  and  so  connected  and  earthed,  that 
they  can  surely  carry  to  ground  any  current 
which  may  be  delivered  by  any  of  the  high- 
pressure  wires.  Further,  the  construction 
.  must  be  such  that  the  guard  wires  will  not  be 
destroyed  by  any  arcing  at  the  point  of  con- 
tact likely  to  occur  under  the  conditions 
existing.  • 

3.  Whenever  neither  of  the  above  methods  is 
feasible,  a  screen  of  wire  should  be  inter- 
posed between  the  lines  at  the  cross-over. 
This  screen  should  be  supported  on  high 
tension  insulators  or  grounded,  and  should 
be  of  such  construction  and  strength  as 
to  prevent  the  upper  wires  from  coming 
into  contact  with  the  lower  ones. 

If  the  screen  is  grounded  each  wire  of  the 
screen  must  be  of  such  size  and  so  connected 
and  earthed  that  it  can  surely  carry  to  ground 
any  current  which  may  be  delivered  by  any  of 
the  high-pressure  wires.  Further,  the  con- 
struction must  be  such  thatthe  wires  of  screen 
will  not  be  destroyed  by  any  arcing  at  the 
point  of  contact  likely  to  occur  under  the  con- 
ditions existing. 

e.  When  it  is  necessary  to  carry  such  lines  near 
buildings,  they  must  be  at  such  height  and  dis- 


24  CLASS    B. — OUTSIDE    WORK. 

12  A,  Constant-Potential  Pole  Lines,  over  5,000  volts— Continued. 
tance  from  the  building  as  not  to  interfere  with 
firemen  in  event  of  fire  ;  therefore,  if  within  25 
feet  of  a  building,  they  must  be  carried  at  a  height 
not  less  than  that  of  the  front  cornice,  and  the 
height  must  be  greater  than  that  of  the  cornice, 
as  the  wires  come  nearer  to  the  building  in  accor- 
dance witli  the  following  table : — 

Distance  of  wire  Elevation  of  wire 

from  building.  above  cornice  of  building. 

Feet.  Feet. 

25  0 

20  2 

15  4 

10  6 

5  8 

2i  9 

It  is  evident  that  where  the  roof  of  the  building  con- 
tinues  nearly  in  line  with  the  walls,  as  in  Mansard 
roofs,  the  height  and  distance  of  the  line  must  be  reck, 
oned  from  some  part  of  the  roof  instead  of  from  the 
cornice. 

13,     Transformers, 

(See  also  Nos.  11,  13  A  and  36.) 

Where  transformers  are  to  be  connected  to  high- 
voltage  circuits,  it  is  necessary  in  many  cases,  for  best 
protection  to  life  and  property,  that  the  secondary  sys- 
tem be  permanently  grounded,  and  provision  should  be 
made  for  it  when  the  transformers  are  built. 

a.  Must  not  be  placed  inside  of  any  building, 
excepting  central  stations  and  sub-stations  (except 
as  provided  in  No.  30  A) ,  unless  by  special  per- 
mission *of    the    Inspection    Department    having 
jurisdiction. 

b.  Must  not  be  attached  to  the  outside  walls  of 
buildings,  unless  separated  therefrom  by  substan- 
tial supports. 

Must  not  be  attached  to  frame  buildings  when 
any  other  location  is  practicable. 


CLASS    B. — OUTSIDE    WORK.  25 


13  A,     Grounding  Low-Potentia!  Circuits, 

The  grounding  of  low-potential  circuits  under  the  fol- 
lowing regulations'is  only  allowed  when  such  circuits 
are  so  arranged  that  under  normal  conditions  of  service 
there  will  be  no  passage  of  current  over  the  ground 
wire. 

IMrect-Current  3- Wire  System*. 

«.  Neutral  wire  may  be  grounded  and  when 
grounded  the  following  rules  nust  be  complied 
with:— 

1.  Must  be  grounded  at  the   Central  Station 

on  a  metal  plate  buried  in  coke  beneath 
permanent  moisture  level,  and  also 
through  all  available  underground  water 
and  gas  pipe  systems. 

2.  In  underground  systems  the  neutral  wire 

must  also  be  grounded  at  each  distribut- 
ing box  through  the  box. 

3.  In  overhead  systems  the  neutral  wire  must 

be  grounded  every  500  feet,  as  provided 
in  Sections  c  to  g. 

Inspection  Departments  having  jurisdiction  may 
require  grounding  if  they  deem  it  necessary. 

Two-wire  direct-current  systems  having  no  accessi- 
ble neutral  point  are  not  to  be  grounded. 

Alternating-Current   Secondary   Systems. 

6.  Transformer  secondaries  of  distributing  sys- 
tems should  preferably  be  grounded,  and  when 
grounded,  the  following  rules  must  be  complied 
with  :— 

1.  The  grounding  must  be  made  at  the  neu- 

tral point  or  wire,  whenever  a  neutral 
point  or  wire  is  accessible. 

2.  When  no  neutral  point  or  wire  is  accessi- 

ble one  side  of  the  secondary  circuit 
may  be  grounded,  provided  the  maxi- 


26  CLASS    B. — OUTSIDE    WORK. 

ISA.    Grounding  Low-Potential  Circuits— Continued, 

mum  difference  of  potential  between  the 
grounded  point  and  any  other  point  in 
the  circuit  does  not  exceed  250  volts. 
3.  The  ground  connection  must  be  at  the 
transformers  or  on  the  individual  service 
as  provided  in  sections  c  to  {/,  and  when 
transformers  feed  systems  with  a  neutral 
wire,  the  neutral  wire  must  also  be 
grounded  at  least  every  250  feet  for  over- 
head systems,  and  every  500  feet  for  un- 
derground systems. 

Inspection  Departments  haying  jurisdiction  may 
require  grounding  if  they  deem  it  necessary. 

Ground  Connection*. 

c.  When  the  ground  connection  is  inside  of  any 
building,  or  the    ground  wire    is    inside   of,    or 
attached  to  any  building  (except  Central  or  Sub- 
stations) the  ground  wire  must  be  of  copper  and 
have   an    approved    rubber    insulating  covering 
National  Electrical  Code  Standard,  for  from  0  to 
600  volts. 

d.  The  ground  wire  in  direct-current  3-wire  sys- 
tems must  not  at  Central  Stations  be  smaller  than 
the  neutral  wire  and  not  smaller  than  No.  4  B.  & 
S.  gage  elsewhere.     The  ground  wire  in  alternat- 
ing-current systems  must  never  be  less  than  No. 
4  B.  &  S.  gage. 

On  three-phase  system,  the  ground  wire  must  have 
a  carrying  capacity  equal  to  that  of  any  one  of  the  three 
mains. 

e.  The  ground  wire  should,  except  for  Central 
Stations   and   transformer   sub-stations,   be   kept 
outside   of  buildings  as  far  as  practicable,   but 
may  be  directly  attached  to  the  building  or  pole 
by  cleats  or  straps  or  on  porcelain  knobs.   Staples 
must  never  be  used.     The  wire  must  be  carried 
in  as  nearly  a  straight  line  as  practicable,  avoid- 


<  CLASS   B.— OUTSIDE    WORK.  27 

13  A,    Grounding  Low-Potential  Circuits— Continued, 

ing  kinks,  coils  and   sharp  bends,  and   must  be 
protected  when  exposed  to  mechanical  injury. 

This  protection  can  be  secured  by  use  of  an  approved 
moulding,  and  as  a  rule  the  ground  wire  on  the  outside 
of  a  building  should  be  in  moulding  at  all  places  where 
it  is  in  within  seven  feet  from  the  ground. 

/.  The  ground  connection  for  Central  Stations, 
transformer  sub-stations,  and  banks  of  trans- 
formers must  be  made  through  metal  plates  buried 
in  coke  below  permanent  moisture  level,  and  con- 
nection should  also  be  made  to  all  available  un- 
derground piping  systems  including  the  lead  sheath 
of  underground  cables. 

fj.  For  individual  transformers  and  building 
services,  the  ground  connection  may  be  made  as 
in  Section/,  or  may  be  made  to  water  piping  sys- 
tems running  into  buildings.  This  connection 
may  be  made  by  carrying  the  ground  wire  into 
the  cellar  and  connecting  on  the  street  side  of 
meters,  main  cocks,  etc. 

Where  it  is  necessary  to  run  the  ground  wire 
through  any  part  of  a  building  it  shall  be  pro- 
tected by  approved  porcelain  bushings  through 
walls  or  partitions  and  shall  be  run  in  approved 
moulding,  except  that  in  basements  it  may  be 
supported  on  porcelain. 

In  connecting  a  ground  wire  to  a  piping  system,  the 
wire  should  be  sweat  into  a  lug  attached  to  an  approved 
clanip,  and  the  clamp  firmly  bolted  to  the  water  pipe 
after  all  rust  and  scale  have  been  removed  ;  or  be  sol- 
dered into  a  brass  plug  and  the  plug  forcibly  screwed 
into  a  pipe-fitting,  or  where  the  pipes  are  cast  iron,  into 
a  hole  tapped  into  the  pipe  itself.  For  large  stations, 
where  connecting  to  underground  pipes  with  bell  and 
spigot  joints,  it  is  well  to  connect  to  several  lengths,  as 
the  pipe  joints  may  be  of  rather  high  resistance. 

Where  ground  plates  are  used^a  No  16  Stubbs'  gage 
copper  plate,  about  three  by  six  feet  in  size,  with  about 
two  feet  of  crushed  coke  or  charcoal.about  pea  size,  both 
under  and  over  it,  would  make  a  ground  of  sufficient 
capacity  for  a  moderate-sized  station,  and  would  prob- 
ably answer  forthe  ordinary  sub-station  or  bank  of  trans- 


28  CLASS    B. — OUTSIDE    WORK. 


ISA,    Grounding  Low-Potential  Circuits— Continued, 

formers.  For  a  large  central  station,  a  plate  with  con- 
siderably more  area  might  be  necessary,  depending 
upon  the  other  underground  connections  available.  The 
ground  wire  should  be  riveted  to  the  plate  in  a  number 
of  places,  and  soldered  for  its  whole  length.  Perhaps 
even  better  than  a  copper  plate  is  a  cast-iron  plate  with 
projecting  forks,  the  idea  of  the  fork  being  to  distribute 
the  connection  to  the  ground  over  a  fairly  broad  area, 
and  to  give  a  large  surface  contact.  The  ground  wire 
can  probably  best  be  connected  to  such  a  cast-iron  plate 
by  soldering  it  into  brass  plugs  screwed  into  holes 
tapped  in  the  plate.  In  all  cases,  the  joint  between  the 
plate  and  the  ground  wire  should  be  thoroughly  pro- 
tected against  corrosion  by  painting  it  with  waterproof 
paint  or  some  equivalent. 


CLASS  C. 

INSIDE    WORK. 

(Light,  Power  and  Heat.     For  signaling  Systems, 
see  Class  E.) 

ALL  SYSTEMS  AND  VOLTAGES. 

GENERAL    RUIZES. 

14,     Wires, 

a.  Must  not  be  of  smaller  size  than  No.  14  B.  & 
S.  gage,  except  as  allowed  for  fixture  work  and 
pendant  cord. 

6.  Tie  wires  must  have  an  insulation  equal  to 
that  of  the  conductors  they  confine.  For  wire 
smaller  than  No.  8  B.  &  S.  gage  split  knobs  or 
cleats  shall  be  used  except  at  dead  ends,  and  tie 
wires  and  knobs  will  not  be  approved. 

Screws  must  be  used  for  fastening  all  cleats  and 
knobs  which  are  arranged  to  grip  the  wire. 

c.  Must  be  so  spliced  or  joined  as  to  be  both 
mechanically  and  electrically  secure  without  sol- 
der. The  joints  must  then  be  soldered  unless 
made  wiUi.  some  form  of  approved  splicing  device, 
and  covered  with  an  insulation  equal  to  that  on 
the  conductors. 

Stranded  Avires  (except  in  flexible  cords)  must 
be  soldered  before  being  fastened  under  clamps  or 
binding  screws,  and  whether  stranded  or  solid, 
when  they  have  a  conductivity  greater  than  that 
of  No.  8  B.  &  S.  gage  they  must  be  soldered  into 
lugs  for  all  terminal  connections,  except  where  an 
approved  solderless  terminal  connector  is  used. 


30  GENERAL    RULES. 

14,    Wires— Continued, 

d.  Must  be  separated  from  contact  with  walls, 
floors,  timbers  or  partitions  through  which  they 
may  pass  by  non-combustible,  non-absorptive,  in- 
sulating tubes,  such  as  glass  or  porcelain,  except 
at  outlets  where  approved  flexible  tubing  is  re- 
quired. 

Bushings  must  be  long  enough  to  bush  the  en- 
tire length  of  the  hole  in  one  continuous  piece,  or 
else  the  hole  must  first  be  bushed  by  a  continuous 
waterproof  tube,  This  tube  may  be  a  conductor, 
such  as  iron  pipe,  but  in  that  case  an  insulating 
bushing  must  be  pushed  into  each  end  of  it,  ex- 
tending far  enough  to  keep  the  wire  absolutely 
out  of  contact  with  the  pipe. 

e.  Must  be  kept  free  from   contact  with   gas, 
water  or  other  metallic  piping,  or  any  other  con- 
ductors or  conducting  material  which  they  may 
cross,  .by  some  continuous  and  firmly  fixed  non- 
conductor,    creating    a    permanent     separation. 
Deviations    from    this    rule    may   sometimes    be 
allowed  by  special  permission. 

Where  tubes  are  used  they  must  be  securely 
fastened  at  the  ends  to  prevent  them  from  moving 
along  the  wire. 

/.  Must  be  so  placed  in  wet  places  that  an  air 
space  will  be  left  between  conductors  and  pipes  in 
crossing,  and  the  former  must  be  run  in-  such  a 
way  that  they  cannot  come  in  contact  with  the 
pipe  accidentally.  Wires  should  be  run  over, 
rather  than  under,  pipes  upon  which  moisture  is 
likely  to  gather  or  which,  by  leaking,  might  cause 
trouble  on  a  circuit. 

g.  The  installation  of  electrical  conductors  in 
wooden  moulding,  or  on  insulators,  in  elevator 
shafts  will  not  be  approved,  but  conductors  may 
be  installed  in  such  shafts  if  encased  in  approved 
metal  conduits. 


INSIDE    WORK.  31 


15,  Underground  Conductors, 

a.  Must  be  protected  against  moisture  and  me- 
chanical injury  where  brought  into   a  building, 
and  all  combustible  material  must  be  kept  from 
the  immediate  vicinity. 

b.  Must  not  be  so  arranged  as  to  shunt  the  cur- 
rent through  a  building  around  any  catch-box. 

c.  Where  underground  service  enters  building 
through  tubes,  the  tubes  shall  be  tightly  closed  at 
outlets  with  asphaltum  or  other  non-conductor, 
to    prevent    gases    from    entering    the    building 
through  such  channels. 

d.  No  underground  service  from  a  subway  to  a 
building    shall   supply   more   than   one  building 
except  by  written  permission  from  the  Inspection 
Department  having  jurisdiction. 

16,  Table  of  Carrying  Capacity  of  Wires, 

a.  The  following  table,  showing  the  allowable 
carrying  capacity  of  copper  wires  and  cables  of 
ninety-eight  per  cent  conductivity,  according  to 
the  standard  adopted  by  the  American  Institute 
of  Electrical  Engineers,  must  be  followed  in 
placing  interior  conductors. 

For  insulated  aluminum  wire  the  safe  carrying 
capacity  is  eighty-four  per  cent  of  that  given  in 
the  following  tables  for  copper  wire  with  the  same 
kind  of  insulation. 


32 


GENERAL   RTLES. 


16.    Table  of  Carrying  Capacity  of  Wires-Continued, 


TABLE  A.          TABLE  B. 
Rubber                 Other 
Insulation.       Insulations.                • 

B.  *&.  G.          Amperes.       Amperes.     Circular  Mils- 

16  

6  

8. 

U  

12  

12  

17  

23. 

6  530 

10  

24  

32. 

8  

6  

46  

4  

G5  

92. 

41  7f) 

3  

2  
1  
0.....  
00  

ooo     

90  
107  
127  
150  
177  

131. 
156. 
185. 
220. 
262 

66,370 
83,690 
105,500 
133,100 
167  goo 

0000  
rcular  Mils. 
200  000              .   . 

210  

200 

312. 

300 
400 

500 

aii^eoo 

400.000... 

330... 

500,000 390 590 

600,000 450..., 680 

700,000 500 760 

800,000 550 840 

900,000 COO 920 

1,000,000 650 1,000 

1,100,000 C90 1,080 

1,200,000 730 1,150 

1,300,000 770 1,220 

1,400,000 810 1,290 

1,500,000 850 1 ,360 

1,600,000 890 1,430 

1,700,000 930 1,490 

1,800,000 970 1,550 

1,900,000 1,010 1,610 

2,000,000 1,050 1,670 

The  lower  limit  is  specified  for  rubber-covered  -wires 
to  prevent  gradual  deterioration  of  the  high  insulations 
by  the  heat  of  the  wires,  but  not  from  fear  of  igniting 
the  insulation.  The  question  of  drop  is  not  taken  into 
consideration  in  the  above  tables. 

The  carrying  capacity  of  Nos.  16  and  18,  B.  &  S.  gage 
wire  is  given,  but  no  smaller  than  No.  14  is  to  be  used, 
except  as  allowed  under  rules  for  fixture  wiring. 


IXSIDE    WORK.  33 


17,'    Switches,  Cut-outs,  Circuit-Breakers,  Etc, 

a.  On  constant  potential  circuits,  all  service 
switches  and  all  switches  controlling  circuits  sup- 
plying current  to  motors  or  heating  devices,  and 
all  fuses,  unless  otherwise  provided  (for  excep- 
tions as  to  switches  see  Nos.  8  c,  23  a  and  34  A — c  ; 
for  exceptions  as  to  cuts-outs  see  No.  21  a  and  6) 
must  be  so  arranged  that  the  fuses  will  protect 
and  the  opening  of  the  switch  will  disconnect  all 
of  the  wires ;  that  is,  in  the  two-wire  system  the 
two  wires,  and  the  three-wire  system  the  three 
wires,  must  be  protected  by  the  fuses  and  discon- 
nected by  the  operation  of  the  switch. 

When  installed  without  other  automatic  over- 
load protective  devices  automatic  overload  circuit 
breakers  must  have  the  poles  and  trip  coils  so 
arranged  as  to  afford  complete  protection  against 
overloads  and  short  circuits,  and  if  also  used  in 
place  of  the  switch  must  be  so  arranged  that  no 
one  pole  can  be  opened  manually  without  discon- 
necting all  the  wires. 

This,  of  course,  does  not  apply  to  the  grounded 
circuit  of  street  railway  systems. 

6.  Must  not  be  placed  in  the  immediate  vicinity 
of  easily  ignitible  stuff  or  where  exposed  to  in- 
flammable gases  or  dust  or  to  flyings  of  combusti- 
ble material. 

When  the  occupancy  of  a  building  is  such  that 
switches,  cut-outs,  etc.,  cannot  be  located  so  as 
not  to  be  exposed  to  dust  or  flyings  of  combustible 
material  they  must  be  enclosed  in  approved  dust- 
proof  cabinets  with  self-closing  doors,  except  oil 
switches  and  circuit  breakers  which  have  dust- 
tight  casings. 

c.  Must,  when  exposed  to  dampness,  either  be 
enclosed  in  a  moisture-proof  box  or  mounted  on 
porcelain  knobs.     The  cover  of  the  box  must  be 
so  made  that  no  moisture  which  may  collect  on 
the  top  or  sides  of  the  box  can  enter  it. 

d.  Time  switches,  sign  flashers  and  similar  ap- 
pliances must  be  of  approved  design  and  enclosed 
in  an  approved  cabinet. 


34  CONSTANT-CURRENT. 


CONSTANT-CURRENT  SYSTEMS, 

PRINCIPALLY  SERIES  ARC  LIGHTING. 

18,    Wires, 

(See  also  Nos.  14,  15  and  16.) 

a.  Must   have   an   approved   rubber   insulating 
covering. 

b.  Must  be   arranged  to   enter  and   leave   the 
building  through  an  approved  double-contact  ser- 
vice switch,  mounted  in  a  non-combustible  case, 
kept  free  from  moisture,  and  easy  of  access  to 
police  or  firemen. 

c.  Must  always  be   in   plain   sight,  and   never 
encased,  except  when  required  by  the  Inspection 
Department  having  jurisdiction. 

t*.  Must  be  supported  on  glass  or  porcelain  in- 
sulators, which  separate  the  wire  at  least  one  inch 
from  the  surface  wired  over  and  must  be  kept 
rigidly  at  least  eight  inches  from  each  other, 
except  within  the  structure  of  lamps,  on  hanger- 
boards  or  in  cut-out  boxes,  or  like  places,  where  a 
less  distance  is  necessary. 

e.  Must,  on  side  walls  be  protected  from 
mechanical  injury  by  a  substantial  boxing,  retain- 
ing an  air  space  of  one  inch  around  the  conduc- 
tors, closed  at  the  top  (the  wires  passing  through 
bushed  holes) ,  and  extending  not  less  than  seven 
feet  from  the  floor.  When  crossing  floor  timbers 
in  cellars,  or  in  rooms  where  they  might  be  ex- 
posed to  injury,  wires  must  be  attached  by  their 
insulating  supports  to  the  under  side  of  a  wooden 
strip  not  less  than  one-half  an  inch  in  thickness. 
Instead  of  the  running-boards,  guard  strips  on 


INSIDE    WOKK.  35 


18,  V/ires-Continued, 

each  side  of  and  close  to  the  wires  will  be 
accepted.  These  strips  to  be  not  less  than  seven- 
eighths  of  an  inch  in  thickness  and  at  least  as  high 
as  the  insulators. 

19,  Series  Arc  Lamps, 

a.  Must  be  carefully  isolated  from  inflammable 
material. 

&.  Must  be  provided  at  all  times  with  a  glass 
globe  surrounding  the  arc,  and  securely  fastened 
upon  a  closed  base.  Broken  or  cracked  globes 
must  not  be  used. 

c.  Must  be  provided  with  a  wire  netting  (having 
a  mesh  not  exceeding  one  and  one-fourth  inches) 
around  the  globe,  and  an  approved  spark  arrester 
when  readily  inflammable  material  is  in  the  vicin- 
ity of  the  lamps,  to  prevent  escape  of  sparks  of 
carbon  or  melted  copper. 

Outside  arc  lamps  must  be  suspended  at  least 
eight  feet  above  sidewalks.  Inside  arc  lamps 
must  be  placed  out  of  reach  or  suitably  protected. 

Arc  lamps,  when  used  in  places  where  they  are 
exposed  to  flyings  of  easily  inflammable  material, 
must  have  the  carbons  enclosed  completely  in  a 
tight  globe  in  such  manner  as  to  avoid  the  neces- 
sity for  spark  arresters. 

"Enclosed    arc"    lamps,    having     tight    inner 

§  lobes,   may  be  used,  and  the   requirements   of 
ections  6  and  c  above  would,  of  course,  not  apply 
to  them. 

d.  Where   hanger-boards  are  not  used,    lamps 
must  be   hung    from   insulating   supports   other 
than  their  conductors. 

e.  Lamps  when  arranged  to  be  raised  arid  low- 
ered, either  for  carboning  or  other  purposes,  shall 
be  connected  up  with  stranded  conductors  from 
the  last  point  of  support  to  the  lamp,  when  such 
conductor  is  larger  than  Xd.  14  B.  &  S.  gage. 


36  COXSTAXT-CUIIRKXT. 

20,     Incandescent  Lamps  in  Series  Circuits, 

a.  Must  have  the  conductors  installed  as  re- 
quired in  No.  18,  and  each  lamp  must  be  provided 
with  an  automatic  cut-out. 

6.  Must  have  each  lamp  suspended  from  a 
hanger-board  by  means  of  rigid  tube. 

c.  No  electro-magnetic  device  for  switches  and 
no   multiple- series   or  series-multiple   system   of 
lighting  will  be  approved. 

d.  Must  not  under  any  circumstances  be  attached 
to  gas  fixtures. 


IX.SIDK    WORK.  37 


CONSTANT-POTENTIAL  SYSTEMS, 

GENERAL  RULES — ALL  VOLTAGES. 

21,     Automatic  Cut-OUtS  (Fuses  and  Circuit-Breakers). 
(See  also  JSTo.  17.) 

a.  Must  be  placed  on  all   service  wires,  either 
overhead  or  underground,  in  the  nearest  access- 
ible place  to  the  point  where  they  enter  the  build- 
ing and  inside  the  walls,  and  arranged  to  cut  off 
the  entire  current  from  the  building. 

Where  the  switch  required  by  No.  22  a  is  inside 
the  building,  the  cut-out  required  by  this  section 
must  be  placed  so  as  to  protect  it. 

For  three-wire  (not  three-phase)  systems  the 
fuse  in  the  neutral  wire  may  be  omitted,  provided 
the  neutral  wire  is  of  equal  carrying  capacity  to 
the  larger  of  the  outside  wires,  and  is  grounded  as 
provided  for  in  No.  13  A. 

In  risks  having  private  plants,  the  yard  wires 
running  from  building  to  building  are  not  consid- 
ered as  service  wires,  so  that  cut-outs  would  not 
be  required  where  the  wires  enter  buildings,  pro- 
vided that  the  next  fuse  back  is  small  enough  to 
properly  protect  the  wires  inside  the  building  in 
question. 

b.  Must  be  placed  at  every  point  where  a  change 
is  made  in  the  size  of  wire  [unless  the  cut-out  in 
the  larger  wire  will  protect  the  smaller  (see  No. 
16.)] 

For  three-wire  (not  three-phase)  systems  the 
fuse  in  the  neutral  wire  except  that  called  for 
under  No.  21  d,  may  be  omitted,  provided  the  neu- 
tral wire  is  of  equal  carrying  capacity  to  the  larger 


38  CONSTANT-POTENTIAL,. 

21,    Automatic  Cut-outs— Continued, 

of  the  outside  wires,  and  is  grounded  as  provided 

for  in  No.  13  A. 

c.  Must  be  in  plain  sight,  or  enclosed  in  an  ap- 
proved cabinet,  and  readily  accessible.     They  must 
not  be  placed  in  the  canopies  or  shells  of  fixtures. 

Link  fuses  may  be  used  only  when  mounted  on 
approved  slate  or  marble  bases  and  must  be  en- 
closed in  dust-tight,  fire-proofed  cabinets,  except 
on  switchboards. 

d.  Must  be  so  placed  that  no  set  of  incandescent 
lamps    requiring    more   than   660  watts,  whether 
grouped  on  one  fixture  or  on  several  fixtures  or 
pendants,  will  be  dependent  upon  one  cut-out. 

Special  permission  may  be  given  in  writing  by 
the  Inspection  Department  having  jurisdiction,  for 
departure  from  this  rule,  in  the  caseof  large  chan- 
deliers. (For  exceptions,  see  rule  on  theatre  wir- 
ing and  List  of  Fittings  for  rules  for  electric  signs.) 
All  branches  or  taps  from  any  three-wire  system 
which  are  directly  connected  to  lamp  sockets  or 
other  translating  devices,  must  be  run  as  two-wire 
circuits  if  the  fuses  are  omitted  in  the  neutral,  or 
if  the  difference  of  potential  between  the  two  out- 
side wires  is  over  250  volts,  and  both  wires  of  such 
branch  or  tap  circuits  must  be  protected  by  proper 
fuses. 

The  above  shall  also  apply  to  motors  when  more 
than  one  is  dependent  on  a  single  cut-out. 

The  fuses  in  the  branch  cut-outs  must  not  have 
a  rated  capacity  greater  than  6  amperes  on  110  volt 
systems,  and  3  amperes  on  220  volt  systems. 

On  open  work  in  large  mills  approvedlink  fused 
rosettes  may  be  used  at  a  voltage  of  not  over  125 
and  approved  enclosed  fused  rosettes  at  a  voltage 
of  not  over  250,  the  fuse  in  the  rosettes  not  to  ex- 
ceed 3  amperes,  and  a  fuse  of  over  25  amperes  must 
not  be  used  in  the  branch  circuit. 

e.  The  rated  capacity  of  fuses  must  not  exceed 
the  allowable  carrying  capacity  of  the  wire  as  given 


INSIDE    WORK.  39 


21,  Automatic  Cut-outs — Continued, 

in  No.  16.  Circuit-breakers  must  not  be  set  more 
than  30  per  cent  above  allowable  carrying  capacity 
of  the  wire,  unless  a  fusible  cut-out  is  also  in- 
stalled on  the  circuit,  in  which  event  the  circuit- 
breaker  may  be  set  as  high  as  100  per  cent  above 
such  capacity. 

In  the  arms  of  fixtures  carrying  a  single  socket 
a  No.  18  B.  &  S.  gage  wire  supplying  only  one 
socket  will  be  considered  as  properly  protected  by 
a  six  ampere  fuse. 

/.  Each  phase  of  A.  C.  motor  circuits,  except 
on  main  switchboard  or  when  otherwise  subject 
to  expert  supervision,  must  be  protected  by  an 
approved  fuse  whether  automatic  overload  cir- 
cuit breakers  are  installed  or  not.  Single  phase 
motors  may  have  one  side  protected  by  an 
approved  automatic  overload  circuit  breaker  only 
if  the  other  side  is  protected  by  an  approved  fuse. 
For  circuits  having  a  maximum  capacity  greater 
than  that  for  which  enclosed  fuses  are  approved 
circuit  breakers  alone  will  be  approved. 

22,  Switches. 

(See  No.  17.") 

a.  Must  be  placed  on  all  service  wires,  either 
overhead  or  underground,  in  the  nearest  readily 
accessible  place,  to  the  point  where  the  wires  enter 
the  building,  and  arranged  to  cut  off  the  entire 
current. 

Service  cut-out  and  switch  must  be  arranged  to 
cut  off  current  from  all  devices  including  meters. 

In  risks  having  private  plants  the  yard  wires 
running  from  building  to  building  are  not  consid- 
ered as  service  wires,  so  that  switches  would  not 
be  required  in  each  building  if  there  are  other 
switches  conveniently  located  on  the  mains  or  if 
the  generators  are  near  at  hand. 


40  CONSTANT-POTENTIAL. 

22,    Switches— Continued, 

b.  Must   always  be    placed   in   dry,  accessible 
places,  and  be  grouped  as  far  as  possible.     (See 
No.  17  c.)     Single-throw  knife  switches  must  be 
so  placed  that  gravity  will  not  tend  to  close  them. 
Double-throw  knife  switches  may  be  mounted  so 
that  the  throw  will  be  either  vertical  or  horizontal 
as  preferred. 

When  practicable  switches  must  be  so  wired 
that  blades  will  be  u  dead  "  when  switch  is  open. 

When  switches  are  used  in  rooms  where  com- 
bustible flyings  would  be  likely  to  accumulate 
around  them,  they  must  be  enclosed  in  dust-tight 
cabinets. 

Up  to  250  volts  and  thirty  amperes,  approved  indicating 
snap  switches  are  suggested  in  preference  to  knife 
switches  on  lighting  circuits. 

c.  Single  pole  switches  must  never  be  used  as 
service  switches  nor  placed  in  the  neutral  wire  of 
a   three-wire    system,    except    in    the    two-wire 
branch  or  tap  circuit  supplying  not   more  than 
660  watts. 

This,  of  course,  does  not  apply  to  the  grounded 
circuits  of  Street  Railway  systems. 

Three- way  switches  are  considered  as  single  pole 
switches  and  must  be  wired  so  that  only  one  pole 
of  the  circuit  is  carried  to  either  switch. 

d.  Where  flush  switches  or  receptacles  are  used, 
whether  with  conduit  systems  or  not,  they  must 
be  enclosed  in  an  approved  box  constructed  of  iron 
or  steel,  in  addition  to  the  porcelain  enclosure  of 
the  switch  or  receptacle.     No   push  buttons  for 
bells,  gas-lighting   circuits,  or  the   like   shall  be 
placed  in  the  same  wall  plate  with  switches  con- 
trolling electric  light  or  power  wiring. 

e.  Where  possible,  at  all  switch  or  fixture  out- 
lets, unless  outlet  boxes  which  will  give   proper 
support  for  fixtures  are  used,   a  7-8  inch  block 
must  be  fastened  between  studs  or  floor  timbers 


IXSIDE    WORK.  41 


22,  Switches— Continued, 

flush  with  the  back  of  lathing  to  hold  tubing, 
and  to  support  switches  or  fixtures.  When  this 
cannot  be  done,  wooden  base  blocks,  not  less  than 
3-4  inch  in  thickness,  securely  screwed  to  lathing, 
must  be  provided  for  switches,  and  also  for  fix- 
tures which  are  not  attached  to  gas  pipes  or  con- 
duit. 

/.  Sub-bases  of  non-combustible,  non-absorptive, 
insulating  material,  which  will  separate  the  wires 
at  least  1-2  inch  from  the  surface  wired  over,  must 
be  installed  under  all  snap  switches  used  in  ex- 
posed knob  and  cleat  work.  Sub-bases  must  also 
be  used  in  moulding  work,  but  they  may  be  made 
of  hardwood  or  they  may  be  omitted  if  the  switch 
is  approved  for  mounting  directly  on  the  moulding. 

23,  Electric  Heaters, 

It  is  often  desirable  to  connect  in  multiple  with  the 
heaters  and  between  the  heater  and  the  switch  control- 
ling same,  an  incandescent  lamp  of  low  candle  power, 
as  it  shows  at  a  glance  whether  or  not  the  switch  is 
open,  and  tends  to  prevent  its  being  left  closed  through 
oversight. 

a.  Must  be  protected  by  a  cut-out  and  controlled 
by  indicating  switches.  Switches  must  be  double 
pole  except  when  the  device  controlled  does  not 
require  more  than  660  watts  of  energy. 

6.  Must  never  be  concealed,  but  must  at  all 
times  be  in  plain  sight.  Special  permission  may 
be  given  in  writing  by  the  Inspection  Department 
having  jurisdiction  for  departure  from  this  rule. 

c.  Flexible  conductors  for  smoothing  irons  and 
sad  irons,  and  for  all  devices  requiring  over  250 
watts    must    have    an    approved   insulation    and 
covering. 

d.  For  portable  heating  devices  the  flexible  con- 
ductors must  be  connected  to  an  approved  plug 
device,  so  arranged   that   the  plug  will   pull  out 


42  CONSTANT-POTENTIAL. 

23,    Electric  Heaters— Continued, 

and  open  the  circuit  in  case  any  abnormal  strain 
is  put  on  the  flexible  conductor.  This  device  may 
be  stationary,  or  it  may  be  placed  in  the  cord 
itself.  The  cable  or  cord  must  be  attached  to  the 
heating  apparatus  in  such  manner  that  it  will  be 
protected  from  kinking,  chafing  or  like  injury  at 
or  near  the  point  of  connection. 

e.  Smoothing  irons,  sad  irons,  and  other  heating 
appliances  that  are  intended  to  be  applied  to  in- 
flammable articles,  such  as  clothing,  must  conform 
to  the  above  rules  so  far  as  they  apply.  They 
must  also  be  provided  with  an  approved  stand,  on 
which  they  should  be  placed  when  not  in  use. 

/.  Stationary  electric  heating  apparatus,  such  as 
radiators,  ranges,  plate  warmers,  etc.,  must  be 
placed  in  a  safe  location,  isolated  from  inflam- 
mable materials,  and  be  treated  as  sources  of  heat. 

Devices  of  this  description  will  often  require  a  suit- 
able heat-resisting  material  placed  between  the  device 
and  its  surroundings.  Such  protection  may  best  be 
secured  by  installing  two  or  more  plates  of  tin  or  sheet 
steel  with  a  one-inch  air  space  between  or  by  alternate 
layers  of  sheet  steel  and  asbestos  with  a  similar  air 
space. 

g.  Must  each  be  provided  with  name-plate,  giv- 
ing the  maker's  name  and  the  normal  capacity  in 
volts  and  amperes. 


INSIDE    WORK.  43 


LOW-POTENTIAL  SYSTEMS, 
550  VOLTS  OK  LESS. 

Any  circuit  attached  to  any  machine,  or  combina- 
tion of  machines,  which  develops  a  difference 
of  potential  between  any  two  wires,  of  over 
ten  volts  and  less  than  550  volts,  shall  be 
considered  as  a  low-potential  circuit,  and  as 
coming  under  this  class,  unless  an  approved 
transforming  device  is  used,  which  cuts  the 
difference  of  potential  down  to  ten  volts  or 
less.  The  primary  circuit  not  to  exceed  a 
potential  of  3,500  volts  unless  the  primary 
wires  are  installed  in  accordance  with  the 
requirements  as  given  in  No.  '12  A,  or  are 
underground.  For  550  volt  motor  equip- 
ments a  margin  of  ten  per  cent  above  the  550 
volt  limit  will  be  allowed  at  the  generator 
or  transformer. 

24,    Wires, 

GENERAL  RULES. 

(See  also  Nos.  14,  15  and  16.) 

a.  Where  entering  cabinets  must  be  protected 
by  approved  bushings,  which  fit  tightly  the  holes 
in  the  box  and  are  well  secured  in  place.    The 
wires  should  completely  fill  the  holes  in  the  bush- 
ings so  as  to  keep  out  the  dust,  tape  being  used 
to  build  up  the  wires  if  necessary.     On  concealed 
knob  and  tube  work  approved  flexible  tubing  will 
be  accepted  in  lieu  of  bushings,  providing  it  shall 
extend  from  the  last  porcelain  support  into  the 
cabinet. 

b.  Must  not  be  laid  in  plaster,  cement  or  similar 
finish,  and  must  never  be  fastened  with  staples. 


44  LOW    CONSTANT-POTENTIAL. 

24,    Wires-Continued, 

c.  Must  not  be  fished   for  any  great  distance, 
and  only  in  places  where  the  inspector  can  satisfy 
himself  that  the  rules  have  been  complied  with. 

d.  Twin  wires  must  never  be  used,  except  in 
conduits,  or  where  flexible  conductors  are  neces- 
sary. 

e.  Must  be  protected  on  side  walls  from  mechani- 
cal injury.     When  crossing   floor  timbers  in  cel- 
lars, or  in  rooms  where  they  might  be  exposed  to 
injury,  wires  must  be  attached  by  their  insulating 
supports  to  the  under  side  of  a  wooden  strip,  not 
less  than  one-half  inch  in  thickness,  and  not  less 
than  three  inches  in  width.     Instead  of  the  run- 
ning-boards, guard  strips  on  each  side  of  and  close 
to  the  wires  will  be  accepted.     These  strips  to  be 
not  less  than  seven-eighths  of  an  inch  in  thickness, 
and  at  least  as  high  as  the  insulators. 

Protection  on  side  walls  must  extend  not  less 
than  five  feet  from  the  floor  and  must  consist  of 
substantial  boxing,  retaining  an  air  space  of  one 
inch  around  the  conductors,  closed  at  the  top  (the 
wires  passing  through  bushed  holes)  or  approved 
metal  conduit  or  pipe  of  equivalent  strength. 

When  metal  conduit  or  pipe  is  used,  the  insula- 
tion of  each  wire  must  be  reinforced  by  approved 
flexible  tubing  extending  from  the  insulator  next 
below  the  pipe  to  the  one  next  above  it,  unless  the 
conduit  is  installed  according  to  No.  25  (sections 
c  and/  excepted),  and  the  wire  is  approved  for 
conduit  use.  The  two  or  more  wires  of  a  circuit 
each  with  its  flexible  tubing  (when  required),  if 
carrying  alternating  current  must,  or  if  direct  cur- 
rent, may  be  placed  within  the  same  pipe. 

In  damp  places  the  wooden  boxing  may  be  prefer- 
able  because  of  the  precautions  which  would  be  neces- 
sary to  secure  proper  insulation  if  the  pipe  were  used. 
With  this  exception,  however,  iron  piping  is  considered 
preferable  to  the  wooden  boxing,  and  its  use  is  strongly 
urged.  It  is  especially  suitable  for  the  protection  of 
wires  near  belts,  pulleys,  etc. 


IXSIDE    WORK.  45 


24,    Wires— Continued,  < 

f.  When  run  in  unfinished  attics,  will  be  con- 
sidered as  concealed,  and  when  run  in  close  prox- 
imity to  water  tanks  or  pipes,  will  be  considered 
as  exposed  to  moisture. 

In  unfinished  attics  wires  are  considered  as  ex- 
posed to  mechanical  injury,  and  must  not  be  run 
on  knobs  on  upper  edge  of  joists. 

SPECIAL   RULES. 

For  Open  Work. 
In  dry  places. 

g.  Must  have  an  approved  rubber,  slow-burning 
weatherproof,  or  slow-burning  insulation. 

A  slow-burning  covering,  that  is,  one  that  will  not 
carry  tire,  is  considered  good  enough  where  the  wires 
are  entirely  on  insulating  supports.  Its  main  object  is 
to  prevent  the  copper  conductors  from  coming  acciden- 
tally into  contact  with  each  other  or  anything  else. 

h.  Must  be  rigidly  supported  on  non-combus- 
tible, non-absorptive  insulators,  which  will  sepa- 
rate the  wires  from  each  other  and  from  the  sur- 
face wired  over  in  accordance  with  the  following 
table  :— 

Voltage.  Distance  from  Distance  "between 

Surface.  Wires. 

0  to  300  5  inch  2|  inch 

301  to  550  1  inch  4  inch 

Rigid  supporting  requires  under  ordinary  condi- 
tions, where  wiring  along  flat  surfaces,  supports 
at  least  every  four  and  one-half  feet.  If  the  wires 
are  liable  to  be  disturbed,  the  distance  between 
supports  must  be  shortened.  In  buildings  of  mill 
construction,  mains  of  not  less  than  No.  8  B.  &  S., 
gage,  where  not  liable  to  be  disturbed,  may  be 
separated  about  six  inches,  and  run  from  timber 
to  timber,  not  breaking  around,  and  may  be  sup- 
ported at  each  timber  only. 

The  neutral  of  an  Edison  three-wire  system  may 


46  LOW    CONSTANT-POTENTIAL. 

24,    Wires— Continued, 

be  placed  in  the  center  of  a  three-wire  cleat  where 
the  difference  of  potential  between  the  outside 
wires  is  not  over  300  volts,  provided  the  outside 
wires  are  separated  two  and  one-half  inches. 

Must  not  be  ''dead-ended"  at  a  rosette  socket 
or  receptacle  unless  the  last  support  is  within 
twelve  inches  of  the  same. 

In  damp  places,  or  buildings  specially  subject  to 
moisture  or  to  acid  or  other  fumes  liable  to 
injure  the  wires  or  their  insulation. 

i.  Must  have  an  approved  insulating  covering. 

For  protection  against  water,  rubber  insulation 
must  be  used.  For  protection  against  corrosive 
vapors,  either  weatherproof  or  rubber  insulation 
must  be  used. 

,;'.  Must  be  rigidly  supported  on  non-combustible, 
non-absorptive  insulators,  which  separate  the  wire 
at  least  one  inch  from  the  surface  wired  over,  and 
must  be  kept  apart  at  least  two  and  one-half 
inches  for  voltages  up  to  300,  and  four  inches  for 
higher  voltages. 

Rigid  supporting  requires  under  ordinary  condi- 
tions, where  wiring  over  flat  surfaces,  supports  at 
least  every  four  and  one-half  feet.  If  the  wires 
are  liable  to  be  disturbed,  the  distance  between 
supports  must  be  shortened.  In  buildings  of  mill 
construction,  mains  of  not  less  than  No.  8  B.  &  S. 
gage,  where  not  liable  to  be  disturbed,  may  be 
separated  about  six  inches,  and  run  from  timber 
to  timber,  not  breaking  around,  and  may  be  sup- 
ported at  each  timber  only. 

For  Moulding  Work  (Wooden  and  Metal). 
(See  No.  25  .1.) 

fc.  Must  have  an  approved  rubber  insulating 
covering,  and  must  be  in  continuous  lengths  from 
outlet  to  outlet,  or  from  fitting  to  fitting,  no  joints 


INSIDE    WOKK.  47 


24.    Wires-Continued. 

or  taps  to  be  made  in  moulding.  Where  branch 
taps  are  necessary  in  moulding  work  approved 
fittings  for  this  purpose  must  be  used. 

I.  Must  never  be  placed  in  either  metal  or 
wooden  moulding  in  concealed  or  damp  places, 
or  where  the  difference  of  potential  between  any 
two  wires  in  the  same  moulding  is  over  300  volts. 
Metal  mouldings  must  not  be  used  for  circuits 
requiring  more  than  660  watts  of  energy. 

in.  Must  for  alternating  current  systems  if  in 
metal  moulding  have  the  two  or  more  wires  of  a 
circuit  installed  in  the  same  moulding. 

It  'is  suggested  that  this  be  done  for  direct  current 
systems  also,  so  that  they  may  be  changed  to  alternat- 
ing systems  at  any  time,  induction  troubles  preventing 
such  a  change  if  the  wires  are  in  separate  mouldings. 

For  Conduit  Work. 

n.  Must  have  an  approved  rubber  insulating 
covering. 

o.  Must  not  be  drawn  in  until  all  mechanical 
work  on  the  building  has  been,  as  far  as  possible, 
completed. 

Conductors  in  vertical  conduit  risers  must  be 
supported  within  the  conduit  system  in  accord- 
ance with  the  following  table : — 

No.  14  to  0  every  100  feet. 
No.  00  to  0000  every  80  feet. 
0000  to  350,000  C.  M.  every  60  feet. 
350,000  C.  M.  to  500,000  C.  M.  every  50  feet. 
500,000  C.  M.  to  750,000  C.  M.  every  40  feet. 
750,000  C.  M.  every  35  feet. 

The  following  methods  of  supporting  cables  are 
recommended : — 

1.  A  turn  of  90  degrees  in  the  conduit  system 

will  constitute  a  satisfactory  support. 

2.  Junction  boxes  may  be  inserted  in  the  con- 

duit system  at  the  required  intervals,  in 


48  LOW    CONSTANT-POTENTIAL. 

24.    Wires— Continued, 

which  insulating  supports  of  approved 
type  must  be  installed  and  secured  in  a 
satisfactory  manner  so  as  to  withstand 
the  weight  of  the  conductors  attached 
thereto,  the  boxes  to  be  provided  with 
proper  covers. 

3.  Cables  may  be  supported  in  approved  junc- 
tion boxes  on  two  or  more  insulating  sup- 
ports so  placed  that  the  conductors  will 
be  deflected  at  an  angle  of  not  less  than 
90  degrees,  and  carried  a  distance  of  not 
less  than  twice  the  diameter  of  the  cable 
from  its  vertical  position.  Cables  so  sus- 
pended may  be  additionally  secured  to 
these  insulators  by  tie  wires. 
Other  methods,  if  used,  must  be  approved  by 
the  Inspection  Departments  having  juris- 
diction. 
p.  Must,  for  alternating  systems,  have  the  two 

or  more   wires  of  a   circuit  drawn   in  the   same 

conduit. 

It  is  suggested  that  this  be  clone  for  direct  current 
systems  also,  so  that  they  may  be  changed  to  alternat- 
ing systems  at  any  time,  induction  troubles  preventing 
such  a  change  if  the  wires  are  in  separate  conduits. 

The  same  conduit  must  not  contain  more  than 
four  two-wire,  or  three  three-wire  circuits  of  the 
same  system,  except  by  special  permission  of  the 
Inspection  Department  having  jurisdiction,  and 
must  never  contain  circuits  of  different  systems. 

For  Concealed  "Knob  and  Tube"  Work. 

q.  Must  have  an  approved  rubber  insulating 
covering. 

r.  Must  be  rigidly  supported  on  non-combusti- 
ble, non-absorptive  insulators  which  separate  the 
wire  at  least  one  inch  from  the  surface  wired 
over.  Should  preferably  be  run  singly  on  sep- 


IX SIDE    WOKK.  49 


24,    Wires— Continued, 

arate  timbers,  or  studding,  and  must  be  kept  at 
least  five  inches  apart. 

Must  be  separated  from  contact  with  the  walls, 
floor  timbers  and  partitions  through  which  they 
may  pass  by  non-combustible,  non-absorptive,  in- 
sulating tubes,  such  as  glass  or  porcelain.  Wires 
passing  through  timbers  at  the  bottom  of  plas- 
tered partitions  must  be  protected  by  an  addi- 
tional tube  extending  at  least  four  inches  above 
the  timber. 

Rigid  supporting  requires,  under  ordinary  con- 
ditions, where  wiring  along  flat  surface,  supports 
at  least  every  four  and  one-half  feet.  If  the  wires 
are  liable  to  be  disturbed  the  distance  between 
supports  must  be  shortened. 

At  distributing  centers,  outlets  or  switches 
where  space  is  limited  and  the  five-inch  separation 
cannot  be  maintained,  each  wire  must  be.  sepa- 
rately encased  in  a  continuous  length  of  approved 
flexible  tubing. 

s.  When  in  a  concealed  knob  and  tube  system, 
it  is  impracticable  to  place  the  whole  of  a  circuit 
on  non-combustible  supports  of  glass  or  porcelain, 
that  portion  of  the  circuit  which  cannot  be  so 
supported  must  be  installed  with  approved  metal 
conduit,  or  approved  armored  cable,  except  that  if 
the  difference  of  potential  between  the  wires  is 
not  over  300  volts,  and  if  the  wires  are  not  exposed 
to  moisture,  they  may  be  fished  if  separately 
encased  in  approved  flexible  tubing,  extending  in 
continuous  lengths  from  porcelain  support  to 
porcelain  support,  from  porcelain  support  to  out- 
let, or  from  outlet  to  outlet.  . 

t.  When  using  either  conduit  or  armored  cable 
in  mixed  concealed  knob  and  tube  work,  the 
requirements  for  conduit  work  or  armored  cable 
work  must  be  complied  with  as  the  case  may  be. 

u.  Must  at  all  outlets,  except  where  conduit  is 
used,  be  protected  by  approved  flexible  tubing, 


50  LOW    CONSTANT-POTENTIAL. 

24,    Wires-Continued, 

•extending  in  continuous  lengths  from  the  last 
porcelain  support  to  at  least  one  inch  beyond 
the  outlet.  In  the  case  of  combination  fixtures 
the  tubes  must  extend  at  least  flush  with  outer 
end  of  gas  cap. 

When  the  surface  at  any  outlet  is  broken,  it 
must  be  repaired  so  as  to  leave  no  holes  or  open 
spaces  at  such  outlet. 

It  is  suggested  that  approved  outlet  boxes  or  plates 
be  installed  at  all  outlets  in  concealed  "  knob  and  tube  " 
work,  the  wires  to  be  protected  by  approved  flexible 
tubing,  extending  in  continuous  lengths  from  the  last 
porcelain  support  into  the  box. 

For  Fixture  Work. 

v.  Must  have  an  approved  rubber  insulating 
covering,  and  be  not  less  in  size  than  No.  18  B.  & 
S.  gage. 

In  wiring  certain  designs  of  show-case  fixtures, 
ceiling  bulls-eyes  and  similar  appliances  in  which 
the  wiring  is  exposed  to  temperatures  in  excess  of 
120  degrees  Fahrenheit  (49  degrees  Centigrade), 
from  the  heat  .of  the  lamps,  approved  slow-burn- 
ing wire  may  be  used.  All  such  forms  of  fixtures 
must  be  submitted  for  examination,  test  and  ap- 
proval before  being  introduced  for  use. 

w.  Supply  conductors,  and  especially  the  splices 
to  fixture  wires,  must  be  kept  clear  of  the  grounded 
part  of  gas  pipes,  and,  where  shells  or  outlet  boxes 
are  used,  they  must  be  made  sufficiently  large  to 
allow  the  fulfillment  of  this  requirement. 

x.  Must,  when  fixtures  are  wired  outside,  be  so 
secured  as  not  to  be  cut  or  abraded  by  the  pres- 
sure of  the  fastenings  or  motion  of  the  fixture. 

y.  Wires  of  different  systems  must  never  be 
contained  in  or  attached  to  the  same  fixture  and 
under  no  circumstances  must  there  be  a  difference 
of  potential  of  more  than  800  volts  between  wires 
contained  in  or  attached  to  the  same  fixture. 


INSIDE  WORK.  51 


24  A,    Armored  Cables, 

a.  Must  be  continuous  from  outlet  to  outlet  or 
to  junction  boxes,  and  the   armor  of  the  cable 
must  properly  enter  and  be  secured  to  all  fittings, 
and  the  entire  system  must  be  mechanically  se- 
cured in  position. 

In  case  of  service  connections  and  main  runs, 
this  involves  running  such  armored  cable  continu- 
ously into  a  main  cut-out  cabinet  or  gutter  sur- 
rounding the  panel  board,  as  the  case  may  be. 

b.  Must  be  equipped  at  every  outlet  with  an 
approved    outlet   box    or    plate,   as    required   in 
conduit  work. 

Outlet  plates  must  not  be  used  where  it  is 
practicable  to  install  outlet  boxes. 

The  outlet  box  or  plate  shall  be  so  installed  that 
it  will  be  flush  with  the  finished  surface,  and  if 
this  surface  is  broken  it  shall  be  repaired  so  that 
it  will  not  show  any  gaps  or  open  spaces  around 
the  edge  of  the  outlet  box  or  plate. 

In  buildings  already  constructed  where  the  con- 
ditions are  such  that  neither  outlet  box  nor  plate 
can  be  installed,  these  appliances  may  be  omitted 
by  special  permission  of  the  Inspection  Depart- 
ment having  jurisdiction,  provided  the  armored1 
cable  is  firmly  and  rigidly  secured  in  place. 

c.  Must  have  the  metal  armor  of  the  cable  per- 
manently and  effectively  grounded. 

Armor  of  cables  and  gas  pipes  must  be  securely 
fastened  in  metal  outlet  boxes  so  as  to  secure 
good  electrical  connection.  Where  boxes  used  for 
centers  of  distribution  do  not  afford  good  elec- 
trical connection  the  armor  of  the  cables  must  be 
joined  around  them  by  suitable  bond  wires. 
Where  sections  of  armored  cable  are  installed 
without  being  fastened  to  the  metal  structure  of 
buildings  or  grounded  metal  piping,  they  must  be 
bonded  together  and  joined  to  a  permanent  and 
efficient  ground  connection. 


52  LOW    COXSTANT-POTEXTIAL. 


24 A,    Armored  Cables— Continued, 

It  is  suggested  that  cables,  outlet  boxes  and  fittings 
having  conductive  coatings  be  used  in  order  to  secure 
better  electi'ical  contact  at  all  points  throughout  the 
cable  system. 

d.  When  installed  in  so-called  fireproof  build- 
ings in   course   of  constriction  or  afterwards  if 
exposed  to  moisture,  or  .mere  it  is  exposed  to  the 
weather,   or  in  damp  places  such  as  breweries, 
stables,  etc.,  the  cable  must  have  a  lead  covering 
at  least  one  thirty-second  inch  in  thickness  placed 
between  the  outer  braid  of  the  conductors  and  the 
steel  armor. 

The  lead  covering  is  not  to  be  required  when 
the  cable  is  run  against  brick  walls  or  laid  in  ordi- 
nary plaster  walls  unless  same  are  continuously 
damp. 

e.  Where  entering  junction  boxes,  and  at   all 
other  outlets,  etc.,  must  be  provided  with  approved 
terminal  fittings  which  will  protect  the  insulation 
of    the   conductors  from  abrasion,   unless    such 
junction  or  outlet  boxes  are  specially  designed 
and  approved  for  use  with  the  cable. 

/.  Junction  boxes  must  always  be  installed  in 
such  a  manner  as  to  be  accessible. 

g.  For  alternating  current  systems  must  have 
the  two  or  more  conductors  of  the  cable  enclosed 
in  one  metal  armor. 

li.  All  bends  must  be  so  made  that  the  armor  of 
the  cable  will  not  be  injured.  The  radius  of  the 
curve  of  the  inner  edge  of  any  bend  not  to  be  less 
than  1$  inches. 

25,     Interior  Conduits, 

(See  also  No.  24  n  to  p.] 

a.  No  conduit  tube  having  an  internal  diameter 
of  less  than  five-eighths  of  an  inch  shall  be  used. 
Measurements  to  be  taken  inside  of  metal  conduits. 

6.  Must  be  continuous  from  outlet  to  outlet  or 


INSIDE    WORK.  53 


25,    Interior  Conduits— Continued. 

to  junction  boxes,  and  the  conduit  must  properly 
enter,  and  be  secured  to  all  fittings  and  the  entire 
system  must  be  mechanically  secured  in  position. 
In  case  of  service  connections  and  main  runs, 
this  involves  running  each  conduit  continuously 
into  a  main  cut-out  cabinet  or  gutter  surrounding 
the  panel  board,  as  the  case  may  be. 

c.  Must  be  first  installed  as  a  complete  conduit 
system,  without  the  conductors. 

d.  Must  be  equipped  at  every  outlet  with  an 
approved  outlet  box  or  plate. 

Outlet  plates  must  not  be  used  where  it  is  prac- 
ticable to  install  outlet  boxes. 

The  outlet  box  or  plate  must  be  so  installed 
that  it  will  be  flush  witli  the  finished  surface,  and 
if  this  surface  is  broken  it  shall  be  repaired  so 
that  it  will  not  show  any  gaps  or  open  spaces 
around  the  edge  of  the  outlet  box  or  plate. 

In  buildings  already  constructed  where  the  con- 
ditions are  such  that  neither  outlet  box  nor  plate 
can  be  installed,  these  appliances  may  be  omitted 
by  special  permission  of  the  Inspection  Depart- 
ment having  jurisdiction,  providing  the  conduit 
ends  are  bushed  and  secured. 

It  is  suggested  that  outlet  boxes  and  fittings  having 
conductive  coatings  be  used  in  order  to  secure  better 
electrical  contact  at  all  points  throughout  the  conduit 
system. 

e.  Metal    conduits   where   they  enter  junction 
boxes,  and  at  all  other  outlets,  etc.,  must  be  pro- 
vided with  approved  bushings  or  fastening  plates 
fitted  so  as  to  protect  wire  from  abrasion,  except 
when    such  protection  is  obtained  by  the  use  of 
approved    nipples,    properly    fitted    in   boxes    or 
devices. 

/.  Must  have  the  metal  of  the  conduit  perma- 
nently and  effectually  grounded. 

Conduits  and  gas  pipes  must  be  securely  fas- 
tened in  metal  outlet  boxes  so  as  to  secure  good 


54  LOW    CONSTANT-POTENTIAL. 

25.    Interior  Conduits— Continued, 

electrical  connection.  If  conduit,  couplings,  out- 
let boxes  or  fittings  having  protective  coating  of 
non-conducting  material,  such  as  enamel,  are 
used,  such  coating  must  be  thoroughly  removed 
from  threads  of  both  couplings  and  conduit  and 
from  surfaces  of  boxes  and  fittings  where  the  con- 
duit is  secured  in  order  to  obtain  the  requisite 
good  connection.  Where  boxes  used  for  centers 
of  distribution  do  not  afford  good  electrical  con- 
nection, the  conduits  must  be  joined  around  them 
by  suitable  bond  wires.  Where  sections  of  metal 
conduit  are  installed  without  being  fastened  to 
the  metal  structure  of  buildings  or  grounded  metal 
piping,  they  must  be  bonded  together  and  joined 
to  a  permanent  and  efficient  ground  connection. 

g.  Junction  boxes  must  always  be  installed  in 
such  a  manner  as  to  be  accessible. 

h.  All  elbows  or  bends  must  be  so  made  that 
the  conduit  or  lining  of  same  will  not  be  injured. 
The  radius  of  the  curve  of  the  inner  edge  of  any 
elbow  not  to  be  less  than  three  and  one-half 
inches.  Must  have  not  more  than  the  equivalent 
of  four  quarter  bends  from  outlet  to  outlet,  the 
bends  at  the  outlets  not  being  counted. 

25  A.     Metal  Mouldings, 

(See  also  No.  24  k  to  m.) 

a.  Must  be  continuous  from  outlet  to  outlet,  to 
junction    boxes,    or   approved    fittings    designed 
especially  for   use  with    metal    mouldings,    and 
must  at  all   outlets  be  provided  with  approved 
terminal   fittings  which  will   protect  the  insula- 
tion of    conductors  from  abrasion,  unless   such 
protection  is  afforded  by  the  construction  of  the 
boxes  or  fittings. 

b.  Such  moulding  where  passing  through  a  floor 
must  be  carried  through  an  iron  pipe  extending 


INSIDE    WOKK.  55 


25  A,    Metal  Mouldings— Continued, 

from  the  ceiling  below  to  a  point  five  feet  above 
the  floor,  which  will  serve  as  an  additional  me- 
chanical protection  and  exclude  tbe  presence  of 
moisture  often  prevalent  in  such  locations. 

In  residences,  office  buildings  and  similar  loca- 
tions where  appearance  is  an  essential  feature, 
and  where  the  mechanical  strength  of  the  mould- 
ing itself  is  adequate,  this  ruling  may  be  modified 
to  require  the  protecting  piping  from  the  ceiling 
below  to  a  point  at  least  three  inches  above  the 
flooring. 

c.  Backing    must    be    secured    in    position  by 
screws  or  bolts,  the  heads  of  which  must  be  flush 
with  the  metal. 

d.  The  metal  of  the  moulding  must  be  perma- 
nently and  effectively  grounded,  and  must  be  so 
installed  that  adjacent  lengths  of  moulding  will 
be  mechanically   and  electrically  secured  at  all 
points. 

Mouldings  and  gas  pipes  must  be  securely  fas- 
tened in  metal  outlet  boxes,  so  as  to  secure  good 
electrical  connection.  Where  boxes  used  for  cen- 
ter of  distribution  do  not  afford  good  electrical 
connection  the  metal  moulding  must  be  joined 
around  them  by  suitable  bond  wires.  Where  sec- 
tions are  installed  without  being  fastened  to  the 
metal  structure  of  the  building  or  grounded  metal 
piping,  they  must  be  bonded  together  or  joined  to 
a  permanent  and  effective  ground  connection. 

It  is  suggested  that  outlet  boxes  and  fittings  having 
conductive  coatings  be  used  in  order  to  secure  better 
electi'ical  contact  at  all  points  throughout  the  conduit 
system. 

e.  Must   be   installed    so    that  for  alternating 
systems  the  two  or  more  wires  of  a  circuit  will  be 
in  the  same  metal  moulding. 

It  is  suggested  that  this  be  done  for  direct  systems 
also,  so  that  they  may  be  changed  to  the  alternating 
system  at  any  time,  induction  troubles  preventing  such 
change  if  the  wires  are  be  in  separate  mouldings. 


56  LOW    CONSTANT-POTENTIAL. 

26,     Fixtures, 

(See  also  Nos.  22  e,  24  v  to  y.) 

a.  Must  when  supported  from  the  gas  piping  or 
any  grounded  metal  work  of  a  building  be  insu- 
lated from  such  piping  or  metal  work  by  means  of 
approved  insulating  joints  placed  as  close  as  pos- 
sible to  the  ceiling  or  walls. 

In  straight  electric  fixtures  where  the  insulation 
of  conductors  and  the  metal  of  fixtures  are  the 
equivalent  of  a  conduit  or  armored  cable  system, 
or  where  used  with  approved  wireless  clusters  or 
where  the  double  braided  wire  extends  directly 
into  an  approved  porcelain  socket,  the  insulating 
joint  may  be  omitted. 

Gas  outlet  pipes  must  be  protected  above  the 
insulating  joint  by  approved  insulating  tubing, 
and  where  outlet  tubes  are  used  they  must  be 
of  sufficient  length  to  extend  below  the  in- 
sulating joint,  and  must  be  so  secured  that 
they  will  not  be  pushed  back  when  the  canopy  is 
put  in  place. 

Fixture  canopies  in  fireproof  buildings  must  be 
thoroughly  and  permanently  insulated  from  walls 
or  ceilings,  and  in  other  than  fireproof  buildings 
they  must  be  thoroughly  and  permanently  insu- 
lated from  metal  walls  or  ceilings  or  from  plaster 
walls  or  ceilings  on  metal  lathing. 

6.  Must  have  all  burs  or  fins  removed  before 
the  conductors  are  drawn  into  the  fixture. 

c.  Must  be  free  from  "contacts"  between  con- 
ductors and  fixture,  "short  circuits1'  and  ground 
connections,  and   must  be   tested  for   such  con- 
ditions before    being  connected    to    the   supply 
conductors. 

d.  All  fixture  arms  made  of  tubing  smaller  than 
1-2  inch  outside  diameter,  also  the  arms  of  all  one- 
light  brackets,  must  be   secured   after  they  are 
screwed  into  position  by  the  use  of  a  set-screw 
properly  placed,  or  by  soldering  or  cementing  or 


INSIDE    WORK. 


5,  Fixtures— Continued, 

some  equally  good  method  to  prevent  the  arms 
from  becoming  unscrewed.  Arms  must  not  be 
made  of  tubing  lighter  than  No.  18  B.  &  S.  gage, 
and  must  have  at  screw  joints  not  less  than  five 
threads  all  engaging.  This  rule  does  not  apply 
to  fixtures  or  brackets  with  cast  or  heavy  arms. 

e.  The  so-called  flat  canopy  sometimes  used  on 
electric  and  combination  fixtures  will  not  be 
approved  except  in  connection  with  outlet  boxes. 

/.  Must,  when  installed  on  the  outside  of  frame 
buildings,  be  of  water-tight  construction. 

g.  Must  not,  when  wired  on  the  outside,  be 
used  in  show  windows  or  in  the  immediate  vicinity 
of  especially  inflammable  stuff. 

27,  Sockets, 

a.  In  rooms  where  inflammable  gases  may  exist 
the  incandescent  lamp  and  socket  must  be  enclosed 
in  a  vapor-tight  globe,  and  supported  on  a  pipe- 
hanger,  wired  with  approved  rubber-covered  wire 
soldered  directly  to  the  circuit. 

6.  In  damp  or  wet  places  "waterproof  "  sockets 
must  be  used.     Unless  made  up  on  fixtures  they 
must  be  hung  by  separate  stranded  rubber-covered 
wires  not  smaller  than  No.  14  B.  &  S.  gage,  which, 
should  preferably  be  twisted  together  when  the 
pendent  is  over  three  feet  long. 

These  wires  must  be  soldered  direct  to  the  cir- 
cuit wires  but  supported  independently  of  them. 

c.  Key  sockets  will  not  be  approved  if  installed 
over  specially  inflammable  stuff,  or  where  ex- 
posed to  flyings  of  combustible  material. 

28,  Flexible  Cord, 

a.  Must  have  an  approved  insulation  and  cover- 
ing. 

6.  Must  not,  except  in  street  railway  property, 
be  used  where  the  difference  of  potential  be- 
tween the  two  wires  is  over  300  volts. 


58  LOW   CONSTANT-POTENTIAL. 

23,    Flexible  Cord— Continued, 

c.  Must  not  be  used  as  a  support  for  clusters. 

d.  Must  not  be  used  except  for  pendants,  wiring 
of  fixtures,  portable  lamps  or  motors,  and  portable 
heating  apparatus. 

For  all  portable  work,  including  those  pendants 
which  are  liable  to  be  moved  about  sufficiently  to 
•come  in  contact  with  surrounding  objects,  flexible 
wires  and  cables  especially  designed  to  withstand 
this  severe  service  must  be  used. 

When  necessary  to  prevent  portable  lamps  from 
•coming  in  contact  with  inflammable  materials,  or 
to  protect  them  from  breakage,  they  must  be  sur- 
rounded with  a  substantial  wire  guard. 

e.  Must  not  be  used  in  show  windows  or  show 
•cases  except  when  provided  with  an   approved 
metal  armor. 

/.  Must  be  protected  by  insulating  bushings 
where  the  cord  enters  the  socket. 

g.  Must  be  so  suspended  that  the  entire  weight 
of  the  socket  and  lamp  will  be  borne  by  some 
approved  method  under  the  bushing  in  the  socket, 
and  above  the  point  where  the  cord  comes  through 
the  ceiling  block  or  rosette,  in  order  that  the  strain 
may  be  taken  from  the  joints  and  binding  screws. 

•29,    Arc  Lamps  on  Constant-Potential  Circuits. 

a.  Must  have  a  cut-out  (see  No.  17  a)  for  each 
lamp  or  each  series  of  lamps. 

The  branch  conductors  must  haye  a  carrying 
capacity  about  fifty  per  cent  in  excess  of  the  nor- 
mal current  required  by  the  lamp. 

6.  Must  only  be  furnished  with  such  resistances 
or  regulators  as  are  enclosed  in  non-combustible 
material,  such  resistances  being  treated  as  sources 
of  heat.  Incandescent  lamps  must  not  be  used  for 
this  purpose. 

c.  Must  be  supplied  with  globes  and  protected 
by  spark  arresters  and  wire  netting  around  the 
globe,  as  in  the  case  of  series  arc  lamps  (see  No. 
19). 


INSIDE    WORK.  59 


29.    Arc  Lamps  on  Constant-Potential  Circuits — Continued, 

Outside  arc  lamps  must  be  suspended  at  least 
eight  feet  above  sidewalks.  Inside  arc  lamps 
must  be  placed  out  of  reach  or  suitably  protected. 

d.  Lamps  when  arranged  to  be  raised  and 
lowered,  either  for  carboning  or  other  purposes, 
shall  be  connected  up  with  stranded  conductors 
from  the  last  point  of  support  to  the  lamp,  when 
such  conductor  is  larger  than  No.  14  B.  &  S.  gage. 

29  A,     Mercury  Vapor  Lamps, 
Enclosed  Mercury  Vapor  Lamps, 

a.  Must  have  cut-out  for  each  lamp  or  series  of 
lamps  except  when  contained  in  single  frame  and 
lighted  by  a  single  operation,  in  which  case  not 
more  than  five  lamps  should  be  dependent  upon 
single  cut-out. 

b.  Must  only  be  furnished  with  such  resistances 
or  regulators  as  are  enclosed  in  non-combustible 
cases,  such  resistances  to  be  treated  as  sources  of 
heat.     In  locations  where    these    resistances  or 
regulators  are  subject  to  flyings  of  lint  or  com- 
bustible material,  all  openings  through  cases  must 
be  protected  by  fine  wire  gauze. 

High  Potential  Vacuum  Tube  Systems, 

c.  The  tube  must  be  so  installed  as  to  be  free 
from  mechanical  injury  or  liability  to  contact  with 
inflammable  material. 

d.  High  potential  coils  and  regulating  apparatus 
must  be  installed  in  approved  steel  cabinet  not  less 
than  1-10  inch  in  thickness  ;  same  to  be  well  venti- 
lated in  such  a  manner  as  to  prevent  the  escape  of 
any   flame  or  sparks,  in  case  of  burnout   in  the 
various  coils.     All  apparatus  in  this  box  must  be 
mounted  on  slate  base  and  the  enclosing  case  posi- 
tively grounded.      Supplying  conductors   leading 
into   this  high  potential   case  to  be  installed   in 
accordance  with  the  standard  requirements  gov- 
erning low  potential  systems,  where  such  wires 
do  not  carry  a  potential  of  over  300  volts. 


60  LOAV    CONSTAXT-POTENTIAL. 

30,  Economy  Coils, 

a.  Economy  and  compensator  coils  for  arc  lamps 
must  be  mounted  on  non-combustible,  non-absorp- 
tive, insulating  supports,  such  as  glass  or  porce- 
lain, allowing  an  air  space  of  at  least  one  inch 
between  frame  and  support,  and  must  in  general 
be  treated  as  sources  of  heat. 

30  A,    Transformers, 

Oil  transformers : — 

a.  Must  not  be  placed  inside  of  any  building 
except  central  stations  and  sub-stations,  unless  by 
special  permission  of   the  inspection  department 
having  jurisdiction. 

Air  cooled  transformers  : — 

The  following  sections  do  not  apply  to 
apparatus  or  fittings,  the  operation  of  which 
depends  either  wholly  or  in  p art  upon  special 
transformers  embodied  in  the  devices,  but  all 
such  apparatus  or  fitting s  must  be  submitted 
for  special  examination  and  cpproval  before 
being  used. 

b.  Must  not  be  placed  inside  of  any  building  ex- 
cepting central  stations  and  sub-stations,  if   the 
highest  voltage  of   either  primary  or   secondary 
exceeds  550  volts. 

c.  Must  be  so  mounted  that  the  case  shall  be  at 
a  distance  of  at  least  one  foot  from  combustible 
material    or    separated    therefrom    by  non-com- 
bustible, non-absorptive,  insulating  material,  such 
as  slate,  marble  or  soapstone.    This  will  require 
the  use  of  a  slab  or  panel  somewhat  larger  than 
the  transformer. 

31,  Decorative  Lighting  Systems, 

a.  Special  permission  may  be  given  in  writing 
by  the  Inspection  Department  having  jurisdiction 
for  the  temporary  installation  of  approved  Systems 


INSIDE    WORK.  61 


31,  Decorative  Lighting  Systems— Continued, 
of  Decorative  Lighting,  provided  the  difference  of 
potential  between  the  wires  of  any  circuit  shall 
not  be  over  150  volts  and  also  provided  that  no 
group  of  lamps  requiring  more  than  1,320  watts 
shall  be  dependent  on  one  cut-out. 

31  A,    Theatre  Wiring, 

(For  rules  governing  Moving  Picture  Machine,  see 

No.  65  A.} 

All  wiring,  apparatus,  etc.,  not  specifically  cov- 
vwed  by  special  rules  herein  given  must  conform  to 
the  standard  Rules  and  Requirements  of  the 
National  Electrical  Code,  and  the  term  "  theatre  " 
shall  mean  a  building  or  part  of  a  building  in  which 
it  is  designed  to  make  a  presentation  of  dramatic, 
operatic  or  other  performances  or  shows  for  the 
entertainment  of  spectators  which  is  capable  of 
seating  at  least  four  hundred  persons,  and  which 
has  a  stage  for  such  performances  that  can  be  used 
for  scenery  and  other  stage  appliances. 

a.    Services, 

1.  Where  source  of  supply  is  outside  of  build- 
ing, there  must  be  at  least  two  separate  and  dis- 
tinct services  where  practicable,  fed  from  separate 
street  mains,  one  service  to  be  of  sufficient 
capacity  to  supply  current  for  the  entire  equip- 
ment of  theatre,  while  the  other  service  must  be 
at  least  of  sufficient  capacity  to  supply  current  for 
all  emergency  lights.  By  " emergency  lights" 
are  meant  exit  lights  and  all  lights  in  lobbies, 
stairways,  corridors  and  other  portions  of  theatre 
to  which  the  public  have  access  which  are  nor- 
mally kept  lighted  during  the  performance. 

This  is  a  matter  solely  concerning  the  protection  of 
the  person  and  should  therefore  be  lef.t  to  the  discretion 
of  the  assured,  so  far  as  the  fire  risk  is  concerned. 


62  LOW    CONSTANT-POTENTIAL. 

31  A,    Theatre  Wiring-Continued, 

2.  Where  source  of  supply  is  an  isolated  plant 
within  same  building,  an  auxiliary  service  of  at 
least  sufficient  capacity  to  supply  all  emergency 
lights  must  be  installed  from  some  outside  source, 
or  a  suitable  storage  battery  within  the  premises 
may  be  considered  the  equivalent  of  such  service. 

This  is  a  matter  solely  concerning  the  protection  of 
the  person  and  should  therefore  be  left  to  the  discretion 
of  the  assured,  so  far  as  the  fire  risk  is  concerned. 

b.    Stage, 

1.  All  permanent  construction  on  stage  side 
of  proscenium  wall  must  be  approved  conduit  or 
armored  cable,  with  the  exception  of  border  and 
switchboard  wiring. 

2.  Switchboards. — Must  be  made  of  non-com- 
bustible,    non-absorptive    material,    and    where 
accessible  from  stage  level  must  be  protected  by 
an  approved  guard-rail  to  prevent  accidental  con- 
tact with  live  parts  on  the  board. 

3.  Footlights:— 

a.  Must  be  wired  in  approved  conduit  or 
armored  cable,  each  lamp  receptable  being 
enclosed  within  an  approved  outlet  box,  the 
whole  to  be  enclosed  in  a  steel  trough,  metal 
to  be  of  a  thickness  not  less  than  No.  20  gage, 
or  each  lamp  receptacle  may  be  mounted  on 
or  in  an  iron  or  steel  box  so  constructed  as 
to  enclose  all  the  wires  and  live  parts  of 
receptacles. 

6.  Must  be  so  wired  that  no  set  of  lamps 
requiring  more  than  1,320  watts  will  be 
dependent  on  one  cut-out. 

4.  Borders: — 

a.  Must  be  constructed  of  steel  of  a  thick- 
ness not  less  than  No.  20  gage,  treated  to 
prevent  oxidization,  be  suitably  stayed  and 


INSIDE    WORK.  63 


31  A,    Theatre  Wiring— Continued, 

supported  by  a  metal  framework,  and  so 
designed  that  flanges  of  reflectors  will  protect 
lamps. 

6.  Must  be  so  wired  that  no  set  of  lamps 
requiring  more  than  1,320  watts  will  be  de- 
pendent upon  one  cut-out. 

c.  Must  be  wired  in  approved  conduit  or 
armored  cable,  each  lamp  receptacle  to  be 
enclosed  within  an  approved  outlet  box,  the 
whole  to  be  enclosed  in  a  steel  trough,  or  each 
lamp  receptacle  may  be  mounted  on  or  in  the 
cover  of  a  steel  box  so  constructed  as  to 
enclose  all  the  wires  and  the  live  parts  of 
receptacles,   metal  to  be  of  a  thickness  not 
less  than  No.  20  gage. 

d.  Must  be  provided  with  suitable  guards 
to   prevent    scenery    or    other    combustible 
material  coming  in  contact  with  lamps. 

e.  Cables  must  be  made  up  of  approved^ 
stranded  rubber-covered  wires  ;  conduit  con- 
struction must  be  used  from  switchboard  to 
point  where  cables  must  be  flexible  to  per- 
mit of  the  raising  and  lowering  of  border,  and 
flexible    portion    must    be     enclosed    in    an 
approved  fireproof  hose  or  braid  and  be  suit- 
ably supported. 

An  approved  junction  box  must  be  in- 
stalled at  the  end  of  the  conduit  where  the 
flexible  cable  leaves  for  the  border. 

/.  For  the  wiring  of  the  border  proper, 
wire  with  approved  slow  burning  insulation 
should  be  used. 

g.  Must  be  suspended  with  wire  rope, 
same  to  be  insulated  from  border  by  at  least 
two  approved  strain  insulators  properly 
inserted. 

5.  Stage  Pockets. — Must  be  of  approved  type 
controlled  from   switchboard,  each  receptacle  to 


64  LOW    CONSTANT-POTENTIAL. 

31  A,    Theatre  Wiring— Continued, 

be  of  not  less  than  fifty  ampers  rating,  and  each 
receptacle  to  be  wired  with  a  separate  circuit  to 
its  full  capacity. 

6.  Proscenium  Side  Lights. — Must  be  so  in- 
stalled that  they  cannot  interfere  with  the  opera- 
tion of  or  come  in  contact  with  curtain. 

7.  Scene  Docks. — Where  lamps  are  installed 
in  Scene  Docks,  they  must  be  so  located  and  in- 
stalled that  they  will  not  be  liable  to  mechanical 
injury. 

8.  Curtain  Motors. — Must  be  of  ironclad  type 
and  installed  so  as  to  conform  to  the  requirements 
of  the  National  Electrical  Code.     (See  No.  8.) 

9.  Control  for  Stage  Flues:— 

a.  In  cases  where  dampers  are  released 
by  an  electric  device,  the  electric  circuit  oper- 
ating same  must  be  normally  closed. 

b.  Magnet    operating    damper    must    be 
wound  to  take  full  voltage  of  circuit  by  which 
it  is  supplied,  using  no  resistance  device,  and 
must  not  heat  more  than  normal  for  appara- 
tus of  similar  construction.     It  must  be  lo- 
cated in  loft  above  scenery,  and  be  installed 
in  a  suitable  iron  box  with  a  tight  self-closing 
door.  ' 

c.  Such  dampers  must  be  controlled  by 
at  least  two  standard   single   pole   switches 
mounted  within  approved  iron  boxes  provided 
with  self-closing  doors  without  lock  or  latch, 
and  located,  one  at  the  Electrician^  station, 
and  others  as  designated  by  the  Inspection 
Department  having  jurisdiction. 

«•    Dressing  Rooms, 

1.  Must    be    wired   in    approved  conduit  or 
armored  cable. 


INSIDE    WORK.  65 


31  A,    Theatre  Wiring-Continued, 

2.  All  pendent  lights  must  be  equipped  with 
approved  reinforced  cord,  armored  cable  or  steel 
armored  flexible  cord. 

3.  All  lamps  must  be  provided  with  approved 
guards. 

d.    Portable  Equipments, 

1.  Arc  lamps  used  for  stage  effects  must  con- 
form to  the  following  requirements  : — 

a.  Must  be  constructed  entirely  of  metal 
except  where  the  use  of  approved  insulating 
material  is  necessary. 

b.  Must  be  substantially  constructed,  and 
so  designed  as  to  provide  for  proper  ventila- 
tion, and  to  prevent  sparks  being  emitted  from 
lamps  when  same  is  in  operation,  and  mica 
must  be  used  for  frame  insulation. 

c.  Front  opening  must  be  provided  with 
a  self-closing  hinged  doorframe  in  which  wire 
gauze  or  glass  must  be   inserted,  excepting 
lens  lamps,  where  the  front  may  be  station- 
ary, and  a  solid  door  be  provided  on  back  or 
side. 

d.  Must  be  provided  with  a  one-sixteenth- 
inch  iron  or  steel  guard  having  a  mesh  not 
larger  than  one   inch,  and   be   substantially 
placed  over  top  and  upper  half  of  sides  and 
back  of  lamp  frame ;    this  guard  to  be  sub- 
stantially riveted  to  frame  of  lamp,  and  to  be 
placed  at  a  distance   of   at   least  two  inches 
from  the  lamp  frame. 

e.  Switch  on  standard  must   be    so  con- 
structed that  accidental  contact  with  any  live 
portion  of  same  will  be  impossible. 

/.  All  stranded  connections  in  lamp  and 
at  switch  and  rheostat  must  be  provided  with 
approved  lugs, 

g.  Rheostat,  if  mounted  on  standard,  must 
be  raised  to  a  height  of  at  least  three  inches 


66  LOW    CONSTANT-POTENTIAL. 

31  A,    Theatre  Wiring — Continued, 

above  floor  line,  and  in  addition  to  being 
properly  enclosed  must  be  surrounded  with  a 
substantially  attached  metal  guard  having  a 
mesh  not  larger  than  one  square  inch,  which 
guard  is  to  be  kept  at  least  one  inch  from 
outside  frame  of  rheostat. 

h.  A  competent  operator  must  be  in 
charge  of  each  arc  lamp,  except  that  one  op- 
erator may  have  charge  of  two  lamps  when 
they  are  not  more  than  ten  feet  apart,  and  are 
so  located  that  he  can  properly  watch  and 
care  for  both  lamps. 

2.  Bunches : — 

a.  Must  be   substantially   constructed  of 
metal,   and    must    not    contain    any  exposed 
wiring. 

b.  The  cable  feeding  samemustbe  bushed 
in  an  approved  manner  where  passing  through 
the  metal,  and  must  be  properly  secured  to 
prevent  any  mechanical  strain  from  coming 
on  the  connection. 

3.  Strips:— 

a.  Must  be     constructed  of    steel  of    a 
thickness  not  less  than  No.  20  gage,  treated 
to  prevent  oxidization,  and  suitably   stayed , 
and  supported  by  metal  framework. 

6.  Cable  feeding  must  be  bushed  in  an 
approved  manner  where  passing  through  the 
metal,  and  must  be  properly  secured  to  pre- 
vent any  mechanical  strain  from  coming  on 
the  connections. 

4.  Portable  Plugging   Boxes. — Must  be    con- 
structed so  that  no  current  carrying  part  will  be 
exposed,  and  each  receptacle  must  be  protected  by 
approved  fuses  mounted  on  slate  or  marble  bases 
and  enclosed  in  a  fireproof  cabinet  equipped  with 


INSIDE    WORK.  '     67 


31  A.    Theatre  Wiring-Continued, 

self-closing  doors.  Each  receptacle  must  be  con- 
structed to  carry  thirty  amperes  without  undue 
heating,  and  the  bus-bars  must  have  a  carrying 
capacity  equivalent  to  the  current  required  for 
the  total  number  of  receptacles,  allowing  thirty 
amperes  to  each  receptacle,  and  approved  lugs 
must  be  provided  for  the  connection  of  the  master 
cable. 

5.  Pin  Plug  Conductors : — 

a.  When  of  approved  type  may  be  used 
to  connect  approved  portable  lights  and  ap- 
pliances. 

b.  Must  be    so    installed    that  the    "fe- 
male "  part  of  plug  will  be  on  the  live  end  of 
cable,  and  must  be  so  constructed  that  tension 
on  the  cable  will  not  cause  any  serious  me- 
chanical strain  on  the  connections. 

6.  Lights   on   Scenery. — Where  brackets    are 
used  they  must  be  wired  entirely  on  the  inside, 
fixture  stem  must  come  through  to  the  back  of 
the  scenery  and  end  of  stem  be  properly  bushed. 

7.  String    or   Festooned  Lights. — Wiring    for 
same  should  be  approved  cable,  joints  where  taps 
are  taken  from  same  for  lights  to  be  properly  made, 
soldered  and  taped,  and  where  lamps  are  used 
in  lanterns  or  similar  devices  lamps  must  be  pro- 
vided with  approved    guards.      Where  taps  are 
taken  from  cable,  they  should  be  so  staggered  that 
joints  of  different  polarity  will  not  come  immedi- 
ately opposite  each  other  and  must  be  properly 
protected  from  strain. 

8.  Special  Electrical  Effects. — Where  devices 
are  used  for  producing  special  effects   such  as 
lightning,  waterfalls,  etc.,  the  apparatus  must  be 
so  constructed  and  located  that  flames,  sparks, 
etc.,  resulting  from  the  operation  cannot  come  in 
contact  with  combustible  material. 


68  LOW   CONSTANT-POTENTIAL. 

31  A,    Theatre  Wiring— Continued, 
e.    Auditorium, 

1.  All   wiring   must  be  installed  in  approved 
conduit  or  armored  cable. 

2.  All  fuses  used   in   connection   with   lights 
illuminating  all  parts  of  the  house  used  by  the 
audience  must  be  installed  in  fireproof  enclosures 
so  constructed  that  there  will  be  a  space   of  at 
least  six  inches  between  the  fuses  and  the  sides 
and  face  of  enclosure. 

3.  Exit  lights  must  not  have  more  than  one 
set  of  fuses  between  same  and  service  fuses. 

4.  Exit  lights  and  all  lights  in  halls,  corridors 
or  any  other  part  of  the  building  used  by  the  au- 
dience, except  the   general   auditorium  lighting, 
must  be  fed  independently  of  the  stage  lighting, 
and  must  be  controlled  only  from  the  lobby  or 
other  convenient  place  in  front  of  the  house. 

5.  Every  portion  of  the  theatre  devoted  to  the 
use  or  accommodation  of  the  public,  also  all  out- 
lets leading  to  the  streets  and  including  all  open 
courts,  corridors,  stairways,  exits  and  emergency 
exit  stairways,  should  be  well  and  properly  lighted 
during  every  performance,  and   the  same  should 
remain  lighted  until  the  entire  audience  has  left 
the  premises. 

31  B,     Outline  Lighting, 

Wiring    (Other    than    Signs    on   Exterior  of 

Buildings)  : — 

a.  Must  be  connected  only  to  low-potential 
-    systems. 

6.  Open  or  conduit  work  may  be  used,  but 
molding  will  not  be  permitted. 

c.  For  open  work,  wires  must  have  an  ap- 
proved rubber  insulating  covering.  Must  be 
rigidly  supported  on  non-combustible,  non- 
absorptive  insulators,  which  separate  the  wires 
at  least  one  inch  from  the  surface  wired  over, 


INSIDE    WORK.  69 


31  B,    Outline  Wiring-Continued, 

and  must  be  kept  apart  at  least  two  and  one- 
half  inches  for  voltages  up  to  300,  and  four 
inches  for  higher  voltages. 

Rigid  supporting  requires,  under  ordinary 
conditions  where  wiring  over  flat  surfaces, 
supports  at  least  every  four  and  one-half  feet. 
If  the  wires  are  liable  to  be  disturbed,  the 
distances  between  supports  should  be  short- 
ened. 

d.  Where  flexible  tubing  is  required,  the 
ends  must  be  sealed  and  painted  with  moisture 
repellant,  and  kept  at  least  one-half  inch  from 
surface  wired  over. 

e.  Wires  for  use  in  rigid  or  flexible  steel 
conduit  must  comply  with  requirements  for 
unlined  conduit  work.     Where  armored  cable 
is   used,   the   conductors   must  be  protected 
from  moisture  by  lead  sheath  between  armor 
and  insulation. 

/.  Must  be  protected  by  its  own  cut-out, 
and  controlled  by  its  own  switch.  Cut-outs, 
switches,  time  switches,  flashers  and  similar 
appliances,  must  be  of  approved  design,  and 
must,  if  located  inside  the  building,  be  in- 
stalled as  required  by  the  code  for  such 
devices.  If  outside  the  building  they  must 
be  enclosed  in  a  steel  or  cast-iron  box. 

If  a  steel  box  is  used,  the  minimum  thick- 
ness of  the  steel  must  be  0.128  of  an  inch 
(Xo.  8  B.  &  S.  gage). 

Boxes  must  be  so  constructed  that  when 
switch  operates  the  blade  shall  clear  the  door 
by  at  least  one  inch,  and  they  must  be  moisture 
proof. 

h.  Circuits  must  be  so  arranged  that  not 
more  than  1,820  watts  will  be  finally  dependent 
upon  a  single  cut-out;  nor  shall  more  than 
C6  sockets  or  receptacles  be  connected  to 
single  circuit- 


70  LOW   CONSTANT-POTENTIAL. 

31  B,    Outline  Wiring-Continued, 

i.  Sockets  and  receptacles  must  be  of  the 
keyless  porcelain  type,  and  wires  must  be 
soldered  to  lugs  on  same. 

32,     Car  Wiring  and  Equipment  of  Cars, 

a.    Protection  of  Car  Body,  etc. 

1.  Under  side  of  far  bodies  to  be  protected  by 
approved   fire-resisting,    insulating  material,   not 
less  than  1-8  inch  in  thickness,  or  by  sheet  iron 
or  steel,  not  less  than  .04  inch  in  thickness,  as 
specified  in  Section  a,  2,  3  and  4.     This  protection 
to  be  provided  over  all  electrical  apparatus,  such 
as  motors  with  a  capacity  of  over  75  II.  P.  each, 
resistances,   contactors,    lightning  arresters,   air- 
brake   motors,   etc.,   and    also  where  wires    are 
run,  except  that  protection  may  be  omitted  over 
wires  designed  to  carry  25  amperes  or  less  if  they 
are  encased  in  metal  conduit. 

2.  At  motors  of  over  75  H.  P.  each,  fire-resist- 
ing material  or  sheet  iron  or  steel  to  extend  not 
less  than  8  inches  beyond  all  edges  of  openings  in 
motors,  and  not  less  than  six  inches  beyond  motor 
leads  on  all  sides. 

3.  Over  resistances,  contactors,  and  lightning 
arresters,  and  other  electrical  apparatus,  excepting 
when  amply  protected  by  their  casing,  fire-resist- 
ing material  or  sheet  iron  or  steel  to  extend  not  less 
than  8  inches  beyond  all  edges  of  the  devices. 

4.  Over  conductors,  not  encased  in  conduit, 
and  conductors  in  conduit  when  designed  to  carry 
over  25  amperes,  unless  the  conduit  is  so  supported 
as  to  give  not  less  than  1-2  inch  clear  air  space  be- 
tween   the    conduit    and    the  car,    fire-resisting 
material  or  sheet  iron  or  steel  to  extend  at  least 
6  inches  beyond  conductors  on  either  side. 

The  fire-resisting  insulating  material  or  sheet 
iron  or  steel  may  be  omitted  over  cables  made  up 


INSIDE    WORK.  rll 


32,    Car  Wiring  and  Equipment  of  Cars— Continued, 
of  flame-proof  braided  outer  covering  when  sur- 
rounded by  1-8  inch  flameproof  covering,  as  called 
for  by  Section  i,  4. 

5.  ±11  all  cases  fireproof  material  or  sheet  iron 
or  steel  to  have  joints  well  fitted,  to  be  securely 
fastened  to  the  sills,  floor  timbers  and  cross  braces, 
and  to  have  the  whole  surface  treated  with  a 
waterproof  paint. 

6.  Cut-out  and  switch  cabinets  to  be  substan- 
tially made  of  hard  wood.     The  entire  inside  of 
cabinet  to  be  lined  with  not  less  than  1-8  inch 
fire-resisting  insulating  material  which  shall  be 
securely  fastened  to  the  woodwork,  and  after  the 
fire-resisting  material  is  in  place  the  inside  of  the 
cabinet  shall  be  treated  with  a  waterproof  paint. 

6.    Wires,  Cables,  etc, 

1.  All  conductors  to  be  stranded,  the  allow- 
able carrying  capacity  being  determined  by  Table 
"  A  "  of  No.  10,  except  that  motor,  trolley  and  re- 
sistance leads  shall  not  be  less  than  No.  7  B.  &  S. 
gage,  heater  circuits  not  less  than  No.  12  B.  &  S. 
gage,  and  lighting  and  other  auxiliary  circuits  not 
less  than  No.  14  B.  &  S.  gage. 

The  current  used  in  determining  the  size  of 
motor,  trolley  and  resistance  leads  shall  be  the  per 
cent  of  the  full  load  current,  based  on  one  hour's 
run  of  the  motor,as  given  by  the  following  table : — 

Size  each  Motor  Trolley  Eesistance 

motor.  Leads.  Leads.  Leads. 

75  H.  P.  or  less  50%           40%  15% 

Over  75  H.  P.  45%           85%  15% 

Approved  fixture  wire  will  be  permitted  for 
wiring  approved  clusters. 

2.  To  have  an  insulation  and  braid  approved 
for  wires  carrying  currents  of  the  same  potential. 

3.  When  run  in  metal  conduit,  to  be  protected 
by  an  additional  braid. 


72  LOW    CONSTANT-POTENTIAL. 

32,    Car  Wiring  and  Equipment  of  Cars— Continued, 

Where  conductors  are  laid  in  conduit,  not 
being  drawn  through,  the  additional  braid  will 
not  be  required. 

4.  When  not  in  conduit,  in  approved  mould- 
ing, or  in  cables   surrounded  by  1-8  inch  flame- 
proof covering,  must  be  approved  rubber  covered 
(except  that  tape  may  be  substituted  for  braid) 
and  be  protected  by  an  additional  flame-proof 
braid,  at  least  1-32  inch  in  thickness,  the  outside 
being  saturated  with  a  preservative  flame-proof 
compound.      Except  that  when  motors  are  so  en- 
closed that  flame  cannot  extend  outside  of  the 
casing,  the  flame-proof  covering  will  not  be  re- 
quired on  the  motor  leads. 

5.  Must  be  so  spliced  or  joined  as  to  be  both 
mechanically    and    electrically    secure    without 
solder.     The  joints  must  then  be  soldered  and 
covered  with  an  insulation  equal   to  that  on  the 
conductors. 

Joints  made  with  approved  splicing  devices 
and  those  connecting  the  leads  at  motors,  plows, 
or  third  rail  shoes  need  not  be  soldered. 

6.  All    connections    of    cables    to    cut-outs, 
switches  and  fittings,  except  those  to  controller 
connection  boards,  when  designed  to  carry  over 
25  amperes,  must  be  provided  with  lugs  or  termi- 
nals soldered  to  the  cable,  and  securely  fastened  to 
the  device,  bjr  bolts,  screws  or  by  clamping ;  or, 
the  end  of  the  cable,  after  the  insulation  is  re- 
moved, shall  be  dipped  in  solder  and  be  fastened 
into  the  device  by  at  least  two  set  screws  having 
check  nuts. 

All  connections  for  conductors  to  fittings,  etc., 
designed  to  carry  less  than  25  amperes,  must  be 
provided  with  up-turned  lugs  that  will  grip  the 
conductor  between  the  screw  and  the  lug,  the 
screws  being  provided  with  flat  washers;  or  by 
block  terminals  having  two  set  screws,  and  the 
end  of  the  conductors  must  be  dipped  in  solder. 


INSIDE    WORK,  73 


32.    Car  Wiring  and  Equipment  of  Cars— Continued. 
Soldering,   in  addition  to  the  connection  of  the 
binding  screws,  is.  strongly  recommended,  and  will 
be  insisted  on  when  above  requirements  are  not 
complied  with. 

This  rule  only  to  apply  to  circuits  where  the 
maximum  potential  is  over  25  volts  and  current 
exceeds  5  amperes. 

c.    Cut-outs,  Circuit  Breakers  and  Switches. 

1.  All  cut-outs  and  switches  having  exposed 
live  metal  parts  to  be  located  in  cabinets.     Cut- 
outs and  switches,  not  in  iron  boxes  or  in  cabinets, 
shall  be  mounted  on  not  less  than  1-4  inch  fire- 
resisting  insulating  material,  which  shall  project 
at  least  1-2  inch  beyond  all  sides  of  the  cut-out  or 
switch. 

2.  Cut-outs  to  be  of  the  approved  cartridge  or 
approved  blow  out  type. 

3.  All  switches  controlling  circuits  of  over  5 
ampere  capacity  shall  be  of  approved  single  pole, 
quick  break  or  approved  magnetic  blow-out  type. 

Switches  controlling  circuits  of  5  ampere  or 
less  capacity  may  be  of  the  approved  single  pole, 
double  break,  snap  type. 

4.  Circuit  breakers  to  be  of  approved  type. 

5.  Circuits  must  not  be  fused  above  their  safe 
carrying  capacity. 

6.  A  cut-out  must  be  placed  as  near  as  possi- 
ble to  the  current  collector,  so  that  the  opening  of 
the  fuse  in  this  cut-out  will  cut  off  all  current 
from  the  car. 

When  cars  are  operated  by  metallic  return 
circuits,  with  circuit  breakers  connected  to  both 
sides  of  the  circuit,  no  fuses  in  addition  to  the 
circuit  breakers  will  be  required. 


74  LOW    CONSTANT-POTENTIAL. 

32,    Car  Wiring  and  Equipment  of  Cars— Continued, 
<l.    Conduit, 

When  from  the  nature  of  the  case,  or  on  account  of 
the  size  of  the  conductors,  the  ordinary  pipe  and  junc- 
tion box  construction  is  not  permissible,  a  special  form 
of  conduit  system  may  be  used,  provided  the  general 
requirements  as  given  below  are  complied  with. 

1.  Metal  conduits,  outlet  and  junction  boxes  to 
be  constructed  in  accordance  with  standard  re- 
quirements except  that  conduit  for  lighting  cir- 
cuits need  not  be  over  5-16  inch  internal  diameter 
and  1-2  inch  external  diameter,  and  for  heating 
and  air  motor  circuits  need  not  be  over  3-8  inch 
internal  diameter  and  9-16  inch  external  diameter, 
and  all  conduits  where  exposed  to  dampness  must 
be  water  tight. 

2.  Must  be  continuous  between  and  be  firmly 
secured  into  all  outlet  or  junction  boxes  and  fit- 
tings, making  a  thorough  mechanical  and  elec- 
trical connection  between  same. 

3.  Metal  conduits,  where  they  enter  all  outlet 
or  junction  boxes  and  fittings,  must  be  provided 
with  approved  bushings  fitted   so  as   to   protect 
cables  from  abrasion. 

4.  Except  as  noted  in  Section  «,  2,  must  have 
the  metal  of  the  conduit  permanently  and  effect- 
ively grounded. 

5.  Junction  and  outlet  boxes  must  be  installed 
in  such  a  manner  as  to  be  accessible. 

6.  All  conduits,  outlets  or  junction  boxes  and 
fittings  to  be  firmly  and  substantially  fastened  to 
the  framework  of  the  car. 

e.    Moulding, 

1.  To  consist  of  a  backing  and  a  capping  and 
to  be  constructed  of  fire-resisting  insulating  mate- 
rial, except  that  it  may  be  made  of  hard  wood 
where  the  circuits  which  it  is  designed  to  support 
are  normally  not  exposed  to  moisture. 

2.  When  constructed  of  fire-resisting  insulat- 
ing material,  the  backing  shall  be  not  less  than  1-4 


INSIDE    WORK. 


32,    Car  Wiring  and  Equipment  of  Cars — Continued, 

inch  in  thickness  and  be  of  a  width  sufficient  to 
extend  not  less  than  1  inch  beyond  conductors  at 
sides. 

The  'capping,  to  be  not  less  than  1-8  inch  in 
thickness  shall  cover  and  extend  at  least  3-4  inch 
beyond  conductors  on  either  side. 

The  joints  in  the  moulding  shall  be  mitred  to 
fit  close,  the  whole  material  being  firmly  secured 
in  place  by  screws  or  nails,  and  treated  on  the  in- 
side and  outside  with  a  waterproof  paint. 

When  fire-resisting  moulding  is  used  over 
surfaces  already  protected  by  1-8  inch  fire-resisting 
insulating  material  no  backing  will  be  required. 

3.  Wooden  mouldings  must  be  so  constructed 
as  to  thoroughly  encase  the  wire  and  provide  a 
thickness  of  not  less  than  3-8  inch  at  the  sides  and 
back  of  the  conductors,  the  capping  being  not  less- 
than  3-16  inch  in  thickness.  Must  have  both  out- 
side and  inside  two  coats  of  waterproof  paint. 

The  backing  and  the  capping  shall  be  secured 
in  place  by  screws. 

/.    Lighting  and  Lighting  Circuits, 

1.  Each  outlet   to  be  provided  with  an   ap- 
proved receptacle,  or  an  approved  cluster.      No 
lamp  consuming  more  than  128  watts  to  be  used. 

2.  Circuits  to  be  run  in  approved  metal  con- 
duit, or  approved  moulding. 

3.  When  metal   conduit   is  used,  except  for 
sign  lights,  all  outlets  to  be  provided  with  ap- 
proved outlet  boxes. 

4.  At  outlet  boxes,   except  where   approved 
clusters  are  used,  receptacles  to  be  fastened  to  the 
inside  of  the  box,  and  the  metal  cover  to  have  an 
insulating  bushing  around  opening  for  the  lamp. 

When  approved  clusters  are  used,  the  cluster 
shall  be  thoroughly  insulated  from  the  metal  con- 


76  LOW    CONSTANT-POTENTIAL. 

32,    Car  Wiring  and  Equipment  of  Cars— Continued. 

duit,  being  mounted  on  a  block  of  hard  wood  or 

fire-resisting  insulating  material. 

5.  Where  conductors  are  run  in  moulding  the 
receptacles  or  cluster  to  be  mounted  on  blocks  of 
hard  wood  or  of  fireproof  insulating  material. 

{/•    Heaters  and  Heating  Circuits, 

1.  Heaters  to  be  of  approved  type. 

2.  Panel  heaters    to   be  so   constructed  and 
located  that  when  heaters  are  in  place  all  current 
carrying  parts  will  be  at  least  4  inches  from  all 
woodwork. 

Heaters  for  cross  seats  to  be  so  located  that 
current  carrying  parts  will  be  at  least  6  inches 
below  under  side  of  seat,  unless  under  side  of  seat 
is  protected  by  not  less  than  1-4  inch  fire-resisting 
insulating  material,  or  .04  inch  sheet  metal  with  1 
inch  air  space  over  same,  when  the  distance  may 
be  reduced  to  3  inches. 

Truss  plank  heaters  to  be  mounted  on  not  less 
than  one-quarter  inch  fire- resisting  insulating  ma- 
terial, the  legs  or  supports  for  the  heaters  pro- 
viding an  air  space  of  not  less  than  one-half  inch 
between  the  back  of  the  heater  and  the  insulating 
material. 

3.  Circuits  to  be  run  in  approved  metal  con- 
duit, or  in  approved  moulding,  or  if  the  location  of 
conductors  is  such  as  will  permit  an  air  space  of 
not  less  than  2  inches  on  all  sides  except  from  the 
surface   wired  over,  they  may  be  supported  on 
porcelain  knobs  or  cleats,  provided  the  knobs  or 
cleats  are  mounted  on  not  less  than  1-4  inch  fire- 
resisting  insulating  material  extending  at  least  3 
inches  beyond  conductors  at  either  side,  the  sup- 
ports raising  the  conductors  not  less  than  1-2  inch 
from  the  surface  wired  over,  and  being  not  over  12 
inches  apart. 

h.    Air  Pump  Motor  and  Circuits, 

1.  Circuits  to  be  run  in  approved  metal  con- 
duit or  JTI  approved  moulding,  except  that  when 


INSIDE    WORK.  77 


32.    Car  Wiring  and  Equipment  of  Cars— Continued, 

run  below  the  floor  of  the  car  they  may  be  sup- 
ported on  porcelain  knobs  or  cleats,  provided  the 
supports  raise  the  conductor  at  least  1-2  inch  from 
the  surface  wired  over  and  are  not  over  12  inches 
apart. 

2.  Automatic  control  to  be  enclosed  in  ap- 
proved metal  box.  Air  pump  and  motor,  when 
enclosed,  to  be  in  approved  metal  box  or  a  wooden 
box  lined  with  metal  of  not  less  than  1-32  inch  in 
thickness. 

When  conductors  are  run  in  metal  conduit  the 
boxes  surrounding  automatic  control  and  air 
pump  and  motor  may  serve  as  outlet  boxes. 


i.    Main  Motor  Circuits  and  Devices. 

1.  Conductors    connecting    between    trolley 
stand  and   main  cut-out  or  circuit  breakers  in 
hood  to  be  protected  where  wires  enter  car  to 
prevent  ingress  of  moisture. 

2.  Conductors  connecting  between  third  rail 
shoes  on  same  truck,  to  be  supported  in  an  ap- 
proved fire-resisting   insulating  moulding,   or  in 
approved  iron  conduit  supported  by  soft  rubber  or 
other  approved  insulating  cleats. 

3.  Conductors  on  the  under  side  of  the  car, 
except  as  noted  in  Section  i,  4,  to  be  supported 
in  accordance  with  one  of  the  following  methods : — 

a.  To  be  run  in  approved  metal  conduit, 
junction  boxes  being  provided  where  branches 
in  conduit  are  made,  and  outlet  boxes  where 
conductors  leave  conduit. 

b.  To  be  run  in  approved  fire-resisting 
insulating  moulding. 

c.  To  be  supported  by  insulating  cleats, 
the  supports  being  not  over  12  inches  apart. 

4.  Conductors  with  flameproof  braided  outer 
Dovering,  connecting  between  controllers  at  either 


78  LOW    CONSTANT-POTENTIAL. 

32.    Car  Wiring  and  Equipment  of  Cars— Continued, 

end  of  car,  or  controllers  and  contactors,  may  be 
run  as  a  cable,  provided  the  cable  where  exposed 
to  the  weather  is  encased  in  a  canvas  hose  or  can- 
vas tape,  thoroughly  taped  or  sewed  at  ends  and 
where  taps  from  the  cable  are  made,  and  the  hose 
or  tape  enters  the  controllers. 

Conductors  with  or  withoutflameproof  braided 
outer  covering  connecting  between  controllers  at 
either  end  of  the  car,  or  controllers  and  contactors, 
may  be  run  as  a  cable,  provided  the  cable  through- 
out its  entire  length  is  surrounded  by  1-8  inch 
flameproof  covering,  thoroughly  taped  or  sewed  at 
ends,  or  where  taps  from  cable  are  made,  and  the 
flameproof  covering  enters  the  controllers. 

Cables  where  run  below  floor  of  car  may  be 
supported  by  approved  insulating  straps  or  cleats. 
Where  run  above  floor  of  car,  to  be  in  a  metal  con- 
duit or  wooden  box  painted  on  the  inside  with  not 
less  than  two  coats  of  flameproof  paint,  and  where 
this  box  is  so  placed  that  it  is  exposed  to  water, 
as  by  washing  of  the  car  floor,  attention  should  be 
given  to  making  the  box  reasonably  waterproof. 

Canvas  hose  or  tape,  or  flameproof  material 
surrounding  cables  after  conductors  are  in  same, 
to  have  not  less  than  two  coats  of  waterproof  in- 
sulating material. 

5.  Motors  to  be   so  drilled  that,  on  double 
truck  cars,  connecting  cables  can  leave  motor  on 
side  nearest  to  king  bolt. 

6.  Resistances  to  be  so  located  that  there  will 
be  at  least  6  inch  air  space  between  resistances 
proper  and  fire-resisting  material  of  the  car.     To 
be  mounted  on  iron  supports,  being  insulated  by 
non-combustible  bushings  or  washers,  or  the  iron 
supports  shall  have  at  least  2  inches  of  insulating 
surface  between  them  and  metal  work  of  car,  or 
the  resistances  may  be  mounted  on  hard  wood 
bars,  supported  by  iron  stirrups,  which  shall  have 
not  less  than  2  inches  of  insulating  surface  be- 


INSIDE    WORK. 


32.  Car  Wiring  and  Equipment  of  Cars— Continued, 

tween  foot  of  resistance  and  metal  stirrup,  the 
entire  surface  of  the  bar  being  covered  with  at 
least  1-8  inch  fire-resisting  insulating  material. 

The  insulation  of  the  conductor,  for  about  6 
inches  from  terminal  of  the  resistance,  should  be 
replaced,  if  any  insulation  is  necessary,  by  a  por- 
celain bushing  or  asbestos  sleeve. 

7.  Controllers  to  be  raised  above  platform  of 
car  by  a  not  less  than  1  inch  hard  wood  block,  the 
block  being  fitted  and  painted  to  prevent  moisture 
working  in  between  it  and  the  platform. 

J-    Lightning  Arresters. 

1.  To  be  preferably  located  to  protect  all  aux- 
iliary circuits  in  addition  to  main  motor  circuits. 

2.  The  ground  conductor  shall   be   not  less 
than  No.  6  B.  &  S.  gage,  run  with  as  few  kinks 
and  bends  as  possible,  and  be  securely  grounded. 

fc.    General  Rules, 

1.  When  passing  through  floors,  conductors 
or  cables  must  be  protected  by  approved  insulat-* 
ing  bushings,  which  shall  fit  the  conductor  or 
cable  as  closely  as  possible. 

2.  Moulding  should  never  be  concealed  except 
where  readily  accessible.    Conductors  should  never 
be  tacked  into  moulding. 

3.  Short    bends    in    conductors    should    be 
avoided  where  possible. 

4.  Sharp    edges   in   conduit  or   in  moulding 
must   be   smoothed    to  prevent    injury    to  con- 
ductors. 

33,  Car  Houses, 

a.  The  trolley  wires  must  be  securely  supported 
on  insulating  hangers. 

6.  The  trolley  hangers  must  be  placed  at  such 
a  distance  apart  that,  in  case  of  a  break  in  the 


SO  LOW   CONSTANT-POTENTIAL. 

33.    Car  Houses-Continued, 

trolley  wire,   contact  with   the  floor  cannot  be 
made. 

c.  Must    have    an    emergency    cut-out    switch 
located  at  a  proper  place  outside  of  the  building, 
so  that  all  the  trolley  wires  in  the  building  may 
be  cut  out  at  one  point,  and  line  insulators  must 
be  installed,  so  that  when  this  emergency  switch 
is  open,  the  trolley  wire  will  be  dead  at  all  points 
within  100  feet  of  the  building.     The  current  must 
be  cut  out  of  the  building  when  not  needed  for 
use  in  the  building. 

This  maybe  done  by  the  emergency  switch,  or  if  pre- 
ferred a  second  switch  may  be  used  that  will  cut  out  all 
current  from  the  building,  but  which  need  not  cut  out 
the  trolley  wire  outside  as  would  be  the  case  with  the 
emergency  switch. 

d.  All  lamps  and  stationary  motors  must  be 
installed  in  such  a  way  that  one  main  switch  may 
control  the  whole  of  each  installation,  lighting  and 
power,  independently  of  the  main  cut-out  switch 
called  for  in  Section  c. 

.  e.  Where  current  for  lighting  and  stationary 
motors  is  from  a  grounded  trolley  circuit,  the 
•following  special  rules  to  apply : — 

1.  Cut-outs  must  be  placed  between  the  non- 

grounded  side  and  lights  or  motors  they 
are  to  protect.  No  set  or  group  of  incan- 
descent lamps  requiring  over  2,000  watts 
must  be  dependent  upon  one  cut-out. 

2.  Switches   must    be    placed    between   non- 

grounded  side  and  lights  and  motors  they 
are  to  protect. 

3.  Must  have  all  rails  bonded  at  each   joint 

with  a  conductor  having  a  carrying  ca- 
pacity at  least  equivalent  to  No.  0  B.  & 
S.  gage  annealed  copper  wire,  and  all 
rails  must  be  connected  to  the  outside 
ground  return  circuit  by  a  not  less  thaji 
Xo.  0  B.  &  S.  gage  copper  wire  or  by 


INSIDE    WORK.  8t 


33.    Car  Houses— Continued, 

equivalent  bonding    through  the   track. 
All  lighting  and  stationary  motor  circuits 
must  be  thoroughly  and  permanently  con- 
nected to  the  rails  or  to  the  wire  leading 
to  the  outside  ground  return  circuit. 
/.  All  pendant  cords  and  portable  conductors 
will  be.  considered  as  subject  to  hard  usage. 

g.  Must,  except  as  provided  in  Section  e,  have 
all  wiring  and  apparatus  installed  in  accordance 
with  the  rules  for  constant  potential  systems. 

h.  Must  not  have  any  system  of  feeder  distri- 
bution centering  in  the  building. 

i.  Cars  must  not  be  left  with  the  trolley  in 
electrical  connection  with  the  trolley  wire. 


34,     Lighting  and  Power  from  Railway  Wires, 

a.  Must  not  be  permitted,  under  any  pretence, 
in  the  same  circuit  with  trolley  wires  with  a 
ground  return,  except  in  electric  railway  cars, 
electric  car  houses,  power  houses,  passenger  and 
freight  stations  connected  with  the  operation  of 
electric  railways. 


34  A,     Electric  Cranes, 

All  wiring,  apparatus,  etc.,  not  specifically 
covered  by  special  rules  herein  given,  must 
conform  to  the  Standard  Rules  and  Re- 
quirements of  the  National  Electrical  Code, 
except  that  the  switch  required  by  Rule 
8c  for  each  motor  may  be  omitted. 

a.    Wiring, 

1.  All  wires  except  bare  collector  wires,  those 
between  resistances  and  contact  plates  of  rheostats 
and  those  subjected  to  severe  external  heat,  must 


82  LOW    CONSTANT-POTENTIAL. 

34  A,    Electric  Cranes— Continued, 

be  approved,  rubber-covered  and  not  smaller  in 
size  than  ]So.  12  B.  &  S.  Insulation  on  wires  be- 
tween resistances  and  contact  plates  of  rheostats 
must  conform  to  Section  d,  while  wires  subjected 
to  severe  external  heat  must  have  approved  slow- 
burning  insulation. 

2.  All  wires   excepting    collector  wires   and 
those  run  in  metal  conduit  or  approved  flexible 
cable  must  be  supported  by  knobs  or  cleats  which 
separate  them  at  least  one  inch  from  the  surface 
wired  over,  but  in  dry  places  where  space  is  limited 
the  distance  between  wires  as  required  by  Rule 
24-ft  cannot  be  obtained,  each  wire  must  be  sepa- 
rately encased  in  approved  flexible  tubing  securely 
fastened  in  place. 

Collector  wires  must  be  supported  by  approved 
insulators  so  mounted  that  even  with  the  extreme 
movement  permitted  the  wires  will  be  separated 
at  all  times  at  least  1  1-2  inches  from  the  surface 
wired  over.  Collector  wires  must  be  held  at  the 
ends  by  approved  strain  insulators. 

3.  Main  collector  wires  carried  along  the  run- 
ways must  be   rigidly  and  securely  attached  to 
their  insulating  supports  at  least  every  20  feet, 
and  separated  at  least  six  inches  when  run  in  a 
horizontal  plane  ;  if  not  run  in  a  horizontal  plane, 
they  must  be  separated  at  least  8  inches.     If  spans 
longer  than  20  feet  are  necessary  the  distance  be- 
tween wires  must  be  increased  proportionately  but 
in  no  case  shall  the  span  exceed  40  feet. 

4.  Where  bridge  collector  wires  are  over  80 
feet  long,  insulating  supports  on  which  the  wires 
may  loosely  lie  must  be  provided  at  least  every  50 
feet. 

Bridge  collector  wires  must  be  kept  at  least 
2  1-2  inches  apart,  but  a  greater  spacing  should  be 
used  whenever  it  may  be  obtained. 


INSIDE    WORK.  83 


34  Ai    Electric  Cranes — Continued, 

5.  Collector  wires  must  not  be  smaller  in  size 
than  specified  in  the  following  table  for  the  vari- 
ous spans. 

Distance  between  Size  wire 

rigid  supports.  required. 

Feet.  B.  &  S. 

0  to  30  6 

31  to  60  4 

Over  60  2 

&•    Collectors, 

Must  be  so  designed  that  sparking  between 
them  and  collector  wires  will  be  reduced  to  a 
minimum. 

c.  Switches  and  Cut-outs, 

1.  The  main  collector  wires  must  be  protected 
by  a  cut-out  and  the  circuit  controlled  by  a  switch. 
Cut-out  and  switch  to  be  so  located  as  to  be  easy  of 
access  from  the  floor. 

2.  Cranes  operated  from  cabs  must  have  a  cut- 
out and  switch  connected  into  the  leads  from  the 
main  collector  wires  and  so  located  in  the  cab  as  to 
be  readily  accessible  to  the  operator. 

3.  Where  there  is  more  than  one  motor  on  a 
single  crane,  each  motor  lead  must  be  protected 
by  a  cut-out  located  in  the  cab  if  there  is  one. 

d.  Controllers, 

Must  be  installed  according  to  No.  4,  except 
that  if  the  crane  is  located  out  doors  the  insula- 
tion on  wires  between  resistances  and  contact 
plates  of  rheostats  must  be  rubber  where  the 
wires  are  exposed  to  moisture  and  insulation  is 
necessary  and  also  where  they  are  grouped.  If 
the  crane  operates  over  readily  combustible  ma- 
terial, the  resistances  must  be  placed  in  an  enclos- 
ure made  of  non-combustible  material,  thoroughly 


84  LOW    CONSTANT-POTENTIAL,. 

34  A,    Electric  Cranes— Continued. 

ventilated  and  so  constructed  that  it  will  not  per- 
mit any  flame  or  molten  metal  to  escape  in  the 
event  of  burning  out  the  resistances.  If  the  re- 
sistances are  located  in  the  cab,  this  result  may  be 
obtained  by  constructing  the  cab  of  non-combusti- 
ble material  and  providing  sides  which  enclose 
the  cab  from  its  floor  to  a  height  at  least  6  inches 
above  the  top  of  the  resistances. 

e.    Grounding  of  Iron  Work. 

The  motor  frames,  the  entire  frame  of  the 
crane  and  the  tracks  must  be  permanently  and 
effectively  grounded. 


INSIDE    WORK.  85 

HIGH-POTENTIAL  SYSTEMS, 
550  TO  3,500  VOLTS. 

Any  circuit  attached  to  any  machine  or  combina- 
tion of  machines  which  develops  a  difference 
of  potential  between  any  two  wires,  of  over 
550  volts  and  less  than  3,500  volts,  shall  be 
considered  at  a  high-potential  circuit,  and  as 
coming  under  that  class,  unless  an  approved 
transforming  device  is  used,  which  cuts  the 
difference  of  potential  down  to  550  volts  or 
less.  For  550  volt  motor  equipments  a  margin 
often  per  cent  above  the  550  volt  limit  will  be 
allowed  at  the  generator  or  transformer  with- 
out coming  under  high-potential  systems. 

35.     Wires, 

(See  also  Nos.  14,  15  and  16.) 

a.  Must   have    an    approved    rubber-insulating 
covering. 

b.  Must  be  always  in  plain  sight  and  never  en- 
cased, except  as  provided  for  in  No.  8  6,  or  where 
required  by  the   Inspection   Department  having 
jurisdiction. 

c.  Must  (except  as  provided  for  in  No.  8  b),  be 
rigidly  supported  011  glass  or  porcelain  insulators, 
which  raise  the  wire  at  least  one  inch  from,  the 
surface  wired  over,  and  must  be  kept  about  eight 
inches  apart. 

Rigid  supporting  requires  under  ordinary  con- 
ditions, where  wiring  along  flat  surfaces,  supports 
at  least  about  every  four  and  one-half  feet.  If  the 
wires  are  unusually  liable  to  be  disturbed,  the 
distance  between  supports  must  be  shortened. 

In  buildings  of  mill  construction,  mains  of  not 
less  than  No.  8  B.  &  S.  gage,  where  not  liable  to 
be  disturbed,  may  be  separated  about  ten  inches 
and  run  from  timber  to  timber,  not  breaking 
around,  and  may  be  supported  at  each  timber 
only. 


HIGH-POTENTIAL   SYSTEMS. 


35,  Wires-Continued, 

d.  Must  be  protected  on  side  walls  from  me- 
chanical injury  by  a  substantial  boxing,  retaining 
an  air  space  of  one  inch  around  the  conductors, 
closed  at  the  top  (the  wires  passing  through 
bushed  holes)  and  extending  not  less  than  seven 
feet  from  the  floor.  When  crossing  floor  timbers, 
in  cellars,  or  in  rooms  where  they  might  be  ex- 
posed to  injury,  wires  must  be  attached  by  their 
insulating  supports  to  the  under  side  of  a  wooden 
strip  not  less  than  one  half  an  inch  in  thickness. 

36,  Transformers,    (When  permitted  inside  build- 

ings under  No.  13.) 

(See  also  Nos.  13  'and  13  A.) 
Transformers  must  not  be  placed  inside  of  build- 
ings without  special  permission  from  the  Inspection 
Department  having  jurisdiction. 

a.  Must  be  located  as  near  as  possible  to  the 
point  at   which    the    primary  wires    enter    the 
building. 

b.  Must  be  placed  in  an  enclosure  constructed  of 
fire-resisting  material ;  the  enclosure  to  be  used 
only  lor  this   purpose,  and  to  be  kept  securely 
locked,  and  access  to  the  same  allowed  only  to  re- 
sponsible parties. 

c.  Must    be    thoroughly    insulated    from    the 
ground,  or  permanently  and  effectually  grounded, 
and  the  enclosure  in  which  they  are  placed  must 
be  practically  air-tight,  except  that  it  must  be 
thoroughly  ventilated  to  the  outdoor  air,  if  pos- 
sible through  a  chimney  or  flue.     There  should  be 
at  least  six  inches  air  space  on  all  sides  of  the 
transformer. 

37,  Series  Lamps, 

a.  No  multiple  series  or  series  multiple  system 
of  lighting  will  be  approved. 

b.  Must  not,  under  any   circumstances,  be  at- 
tached to  gas  fixtures. 


INSIDE    WORK.  87 


EXTRA-HIGH-POTENTIAL  SYSTEMS. 
OVER  3,500  VOLTS. 

Ang  circuit  attached  to  any  machine  or  combina- 
tion of  machines  which  develops  a  difference 
of  potential,  between  any  two  wires,  of  over 
3,500  volts,  shall  be  considered  as  an  extra- 
high-potential  circuit,  and  as  coming  under 
that  class,  unless  an  approved  transforming 
device  is  used,  which  cuts  the  difference  of 
potential  down  to  3,500  volts  or  less. 

38,  Primary  Wires, 

a.  Must  not  be  brought  into  or  over  buildings, 
except  power  stations  and  sub-stations. 

39,  Secondary  Wires. 

a.  Must  be  installed  under  rules  for  high-poten- 
tial systems  when  their  immediate  primary  wires 
iarry  a  current  at  a  potential  of  over  3,500  volts, 
inless  the  primary  wires  are  installed  in  accord- 
ince  with  the  requirements  as  given  in  No.  12  A 
^r  are  entirely  underground,  within  city,  town 
ind  village  limits. 


CLASS  D 

Containing  rules  No.  40  to  63  inclusive  relating  to 
Construction  of  Fittings  and  Materials  is  omitted 
from  this  pamphlet. 


88  CLASS    E. 


CLASS  E. 
MISCELLANEOUS. 

64,     Signaling  Systems, 

Governing  wiring  for  telephone,  telegraph,  dis- 
trict messenger  and  call-bell  circuits,  fire  and  bur- 
glar alarms,  and  all  similar  systems  which  are 
hazardous  only  because  of  their  liability  to  become 
crossed  with  electric  light,  heat  or  power  circuits. 

a.  Outside  wires  should  be  run  in  underground 
ducts  or  strung  on  poles,  and  kept  off  of  the  roofs 
of  buildings,  except  by  special  permission  of  the 
Inspection  Department  having  jurisdiction,  and 
must  not  be  placed  on  the  same  cross-arm  with 
electric  light  or  power  wires.     They  should  not 
occupy  the  same  duct,  manhole  or  handhole  of 
conduit  systems  with  electric  light  or  power  wires. 

Single  manholes,  or  handholes  separated  into 
sections  by  means  of  partitions  of  brick  or  tile  will 
be  considered  as  conforming  with  the  above  rule. 

The  liability  of  accidental  crossing  of  overhead  sig- 
naling circuits  with  electric  light  and  power  circuits 
may  be  guarded  against  to  a  considerable  extent  by 
endeavoring  to  keep  the  two  classes  of  circuits  on  dif- 
ferent sides  of  the  same  street. 

When  the  entire  circuit  from  Central   Station  to 

building   i*   run   in   underground,  conduits, 

Sections   b  to  m  inclusive  do  not  apply. 

b.  When  outside  wires  are  run  on  same  pole 
with  electric  light  or  power  wires,  the   distance 
between  the  two   inside  pins  of   each   cross-arm 
must  not  be  less  than  twenty-four  inches. 

Signaling  wires  being  smaller  and  more  liable  to 
break  and  fall,  should  generally  be  placed  on  the  lower 
cross-arms. 


MISCELLANEOUS.  89 

64,    Signaling  Systems— Continued, 

When  the  wires  are  carried  in  approved  cables, 
the  next  three  sections  (c,  d  and  e)  do  not  apply. 

c.  Where  wires  are  attached  to  the  outside  walls 
of  buildings,  they  must  have  an  approved  rubber 
insulating  covering,  and  on  frame  buildings  or 
frame  portions   of  other  buildings  shall  be  sup- 
ported on  glass  or  porcelain  insulators,  or  knobs. 

d.  The  wires  from  last  outside  support  to  the 
cut-outs  or  protectors  mustbe  of  copper,  and  must 
have  an  approved  rubber  insulation  must  be  pro- 
vided with   drip  loops  immediately  outside  the 
building  and  at  entrance ;  must  be  kept  not  less 
than  two  and  one-half  inches  apart. 

e.  Wires  must  enter  building  through  approved 
non-combnstible,  non-absorptive,  insulating  bush- 
ings sloping  upward  from  the  outside. 

Installations  where  the  Current  Carrying  Parts 
of  the  Apparatus  Installed  are  Capable  of 
Carrying  Indefinitely  a  Current  of  Ten 
Amperes. 

f.  An  all-metallic  circuit  shall  be  provided,  ex- 
cept in  telegraph  systems. 

g.  At  the   entrance   of  wires   to  building,  ap- 
proved single  pole  cut-outs,  designed  for  251-600 
volts  potential  and  containing  fuses  rated  at  not 
over  ten  amperes  capacity,  shall  be  provided  for 
each  wire.     These  cut-outs  must  not  be  placed  in 
the  immediate  vicinity  of  easily  ignitible  stuff,  or 
where  exposed  to  inflammable  gases,  or  dust  or 
to  flyings  of  combustible  material. 

h.  The  wires  inside  building  shall  be  of  copper 
not  less  than  !No.  16  B.  &  S.  gage,  and  must  have 
insulation  and  be  supported,  the  same  as  would 
be  required  for  an  installation  of  electric  light  or 
power  wiring,  0-600  volts  potential. 

i.  The  instruments  shall  be  mounted  on  bases 
constructed  of  non-combustible,  non-absorptive, 


90  CLASS   E. 


64,    Signaling  Systems— Continued, 

insulating  material.  Holes  for  the  supporting 
screws  must  be  so  located,  or  countersunk,  that 
there  will  be  at  least  one-half  inch  space,  meas- 
ured over  the  surface,  between  the  head  of  the 
screw  and  the  nearest  live  metal  part. 

Installations  where  the  Current  Carrying  Parts  of 
the    Apparatus    Installed    are    Not    Capable 
j  of  Carrying    Indefinitely   a    Current    of  Ten 
Amperes. 

j.  Must  be  provided  with  an  approved  protective 
device  located  as  near  as  possible  to  the  entrance 
of  wires  to- building.  The  protector  must  not  be 
placed  in  the  immediate  vicinity  of  easily  ignitible 
stuff,  or  where  exposed  to  inflammable  gases  or 
dust  or  flyings  of  combustible  materials. 

k.  Wires  from  entrance  to  building  to  protector 
must  be  supported  on  porcelain  insulators,  so  that 
they  will  come  in  contact  with  nothing  except 
their  designed  supports. 

I.  The  ground  wire  of  the  protective  device 
shall  be  run  in  accordance  with  the  following 
requirements : — 

1.  Shall  be  of  copper  and  not  smaller  than 

No.  18  B.  &  S.  gage. 

2.  Must  have  an  insulating  covering  approved 

for  voltages  from  0  to  600,  except  that 
the  preservative  compound  may  be 
omitted. 

3.  Must  run  in  as  straight  a  fine  as  possible  to 

a  good  permanent  ground.  This  may  be 
obtained  by  connecting  to  a  water  or  gas 
pipe  connected  to  the  street  mains  or  to  a 
ground  rod  or  pipe  driven  in  permanently 
damp  earth.  When  connections  are  made 
to  pipes,  preference  shall  be  given  to 
water  pipes.  If  attachment  is  made  to 


MISCELLANEOUS.  91 


64,    Signaling  Systems— Continued, 

gas  pipe,  the  connection  in  all  cases  must 
be  made  between  the  meter  and  the  street 
mains.  In  every  case  the  connection  shall 
be  made  as  near  as  possible  to  the  earth. 

When  the  ground  wire  is  attached  to  a  water 
pipe  or  a  gas  pipe,  it  may  be  connected 
by  means  of  an  approved  ground  clamp 
fastened  to  a  thoroughly  clean  portion  of 
said  pipe,  or  the  pipe  shall  be  thoroughly 
cleaned  and  tinned  with  rosin  flux  solder, 
and  the  ground  wire  shall  then  be  wrapped 
tightly  around  the  pipe  and  thoroughly 
soldered  to  it. 

When  the  ground  wire  is  attached  to  a  ground 
rod  driven  into  the  earth,  the  ground  wire 
shall  be  soldered  to  the  rod  in  a  similar 
manner. 

Steam  or  hot-water  pipes  must  not  be  used 

for  a  protector  ground. 

in.  The  protector  to  be  approved  must  comply 
witli  the  following  requirements  : — 

For  Instrument  Circuits  of  Telegraph  Systems, 

1.  An  approved  single  pole  cut-out,  in  each 
wire,  designed  for  2,000  volts  potential, 
and  containing  fuses  rated  at  not  over 
one  ampere  capacity.  When  main  line 
cut-outs  are  installed  as  called  for  in  sec- 
tion gr,  the  instrument  cut-outs  may  be 
placed  between  the  switchboard  and  the 
instrument  as  near  the  switchboard  as 
possible. 

For  All  Other  Systems, 

1.  Must  be  mounted  on  non-combustible,  non- 
absorptive,  insulating  bases,  so  designed 
that  when  the  protector  is  in  place,  all 
parts  which  may  be  alive  will  be  thor- 
oughly insulated  from  the  wall  to  which 
the  protector  is  attached. 


92  CLASS    K. 


64,    Signaling  Systems— Continued, 

2.  Must  have  the  following  parts : — 

A  lightning  arrester  which  will  operate  with  a 
difference  of  potential  between  wires  of 
not  over  500  volts,  and  so  arranged  that 
the  chance  of  accidental  grounding  is 
reduced  to  a  minimum. 

A  fuse  designed  to  open  the  circuit  in  case  the 
wires  become  crossed  with  light  or  power 
circuits.  The  fuse  must  be  able  to  open 
the  circuit  without  arcing  or  serious  flash- 
ing when  crossed  with  any  ordinary  com- 
mercial light  or  power  circuit. 

A  heat  coil,  if  the  sensitiveness  of  the  instru- 
ment demands  it, which  will  operate  before 
a  sneak  current  can  damage  the  instru- 
ment the  protector  is  guarding. 

Heat  coils  are  necessary  in  all  circuits  nor- 
mally closed  through  magnet  windings, 
which  cannot  indefinitely  carry  a  current 
of  at  least  five  amperes. 

The  heat  coil  is  designed,  to  warm  up  and  melt  out 
with  a  current  large  enough  to  endanger  the 
instruments  if  continued  for  a  long  time,  but 
so  small  that  it  would  not  blow  the  fuses  or- 
dinarily found  necessary  for  such  instru- 
ments. The  smaller  currents  are  oft«n  called 
"  sneak  "  currents. 

3.  The  fuses  must  be  so  placed  as  to  protect 
the  arrester  and  heat  coils,  and  the  pro- 
tector terminals  must  be  plainly  marked 
"line,"  " instrument,"  "ground." 

An  easily  read  abbreviation  of  the  above 
words  will  be  allowed. 


MISCELLANEOUS. 


64,  Signaling  Systems— Continued, 

The  "Following  Rules  Apply  to  All  System* 
whether  the  Wires  from  the  Central  Office 
to  the  Building  are  Overhead  or  Under- 
ground. 

7i.  Wires  beyond  the  protector,  or  wires  inside 
buildings  where  no  protector  is  used,  must  be 
neatly  arranged  and  securely  fastened  in  place  in 
some  convenient,  workmanlike  manner. 

They  must  not  come  nearer  than  three  inches 
to  any  electric  light  or  power  wire  in  the  building, 
unless  separated  therefrom  by  some  continuous 
and  firmly  fixed  non-conductor  creating  a  perma- 
nent separation ;  this  non-conductor  to  be  in 
addition  to  the  regular  insulation  on  the  wire. 

The  wires  would  ordinarily  be  insulated,  but  the  kind 
of  insulation  is  not  specified,  as  the  protector  is  relied 
upon  to  stop  all  dangerous  currents.  Porcelain  tubing 
or  approved  flexible  tubing  may  be  used  for  encasing 
wires  where  required  as  above. 

o.  Wires  where  bunched  together  in  a  vertical 
run  within  any  building  must  have  a  fire-resisting 
covering  sufficient  to  prevent  the  wires  from 
carrying  fire  from  floor  to  floor  unless  they  are 
run  either  in  non-combustible  tubing  or  in  a  fire- 
proof shaft,  which  shaft  must  be  provided  with 
fire  stops  at  each  floor. 

Signaling  wires  and  electric  light  or  power 
wires  may  be  run  in  the  same  shaft,  provided 
that  one  of  these  classes  of  wires  is  run  in  non- 
combustible  tubing,  or  provided  that  when  run 
otherwise  these  two  classes  of  wires  shall  be 
separated  from  each  other  by  at  least  two  inches. 

In  no  case  shall  signaling  wires  be  run  in  the 
same  tube  with  electric  light  or  power  wires. 

65,  Electric  Gas  Lighting, 

a.  Electric  gas  lighting,  unless  it  is  the  fric- 
tional  system,  must  not  be  used  on  the  same  fix- 
ture with  the  electric  light. 


94  CLASS   E. 


65  A,     Moving  Picture  Machines, 

a.  Arc  lamp  used  as  a  part  of  moving  picture 
machines   must    be  constructed    similar    to    arc 
lamps  of  theatres,  and  wiring  of  same  must  not 
be  of  less  capacity  than  No.  0  B.  &  S.  gage.     (See 
No.  31Ad.  [1].) 

b.  Rheostats  must  conform  to  rheostat  require- 
ments for  theatre  arcs.     (See  No.  31 A  d.  [1].) 

c.  Top  reel  must  be  encased  in  a  steel  box  with 
hole  at  the  bottom  only  large  enough  for  film  to 
pass  through,  and  cover  so  arranged  that  this 
hole  can  be  instantly  closed.     No  solder  to  be 
used  in  the  construction  of  this  box. 

d.  A  steel  box  must  be  used,  for  receiving  the 
film  after  being  shown,  with  a  hole  in  the  top  only 
large  enough  for  the  film  to  pass  through  freely, 
with  a  cover  so  arranged  that  this  hole  can  be 
instantly  closed.     An  opening  may  be  placed  at 
the  side  of  the  box  to  take  the  film  out,  with  a 
door  hung  at  the  top,  so  arranged  that  it  cannot 
be   entirely   opened,   and    provided  with   spring 
catch  to  lock  it  closed.     No  solder  to  be  used  in 
the  construction  of  this  box. 

e.  The  handle  or  crank  used  in  operating  the 
machine  must  be  secured  to  the  spindle  or  shaft, 
so  that  there  will  be  no  liability  of  its  coming  off 
and  allowing  the  film  to  stop  in  front  of  lamp.  - 

/.  A  shutter  must  be  placed  in  front  of  the 
condenser,  arranged  so  as  to  be  readily  closed. 

g.  Extra  films  must  be  kept  in  metal  box  with 
tight  fitting  cover. 

h.  Machines  must  be  operated  by  hand  (motor 
driven  will  not  be  permitted) . 

i.  Picture  machine  must  be  placed  in  an  en- 
closure or  house  made  of  suitable  fireproof  ma- 
terial, be  thoroughly  ventilated  and  large  enough 
for  operator  to  walk  freely  on  either  side  of  or 
back  of  machine.  All  openings  into  this  booth 
must  be  arranged  so  as  to  be  entirely  closed  by 


MISCELLANEOUS. 


95 


65  A,    Moving  Picture  Machines— Continued, 

doors  or  shutters  constructed  of  the  same  or 
equally  good  fire-resisting  material  as  the  booth 
itself.  Doors  or  covers  must  be  arranged  so  as  to 
be  held  normally  closed  by  spring  hinges  or 
equivalent  devices. 

66,     Insulation  Resistance, 

The  wiring  in  any  building  must  test  free  from 
grounds  ;  i.  e.,  the  complete  installation  must  have 
an  insulation  between  conductors  and  between  all 
conductors  and  the  ground  (not  including  attach- 
ments, sockets,  receptacles,  etc.)  not  less  than 
that  given  in  the  following  table: — 


Up 

( 

to         5 
10 
25 

50 
100 
200 
400 
800 
1       1,600 

amf 

( 
( 

>eres  4,000,000  oh 
...  2,000,000 
800,000 
400,000 
200,000 
100,000 
50,000 
25  000 

ins. 

12,500 

The  test  must  be  made  with  all  cut-outs  and 
safety  devices  in  place.  If  the  lamp  sockets, 
receptacles,  electroliers,  etc.,  are  also  connected, 
only  one  half  of  the  resistances  specified  in  the 
table  will  be  required. 

67.     Soldering  Fluid, 

<i.  The  following  formula  for  soldering  fluid  is 
suggested : — 

Saturated  solution  of  zinc  chloride 5  parts 

Alcohol 4  parts 

Glycerine 1  part 


INDEX. 


Classen  A,  It,  C  and 


NUMBER  AND 

SECTION. 

Acid  fumes 10  (c)  &  24  (i)  to  24  (fc) 

Arc  lamps,  location  requirements 19  (c)  &  29  (c) 

Arc  lamps  on  constant-current  systems 19 

Arc  lamps  on  constant-potential  systems 29 

Armored  Cable,  Installation  of 24  (s)  &  24  A 

Armored  Cable,  Metallic  sheaths  to  be  grounded  12  (i)  & 

24  A  (c) 
Attendance j 

Halanciug  coils  on  three-wire  systems.     (See  Reactive 

Coils.) 

Base-frames  for  generators  and  motors 1  (c)  &  8  (a) 

Batteries,  .storage  and  primary 10 

Bell  wires    .  64 

Binding  screws  not  to  bear  strain 28  (g) 

Blocks  at  fixture  and  switch  outlets 22  (e) 

Bonds  required  on  rails  in  car  houses 33  (g) 

Boxing  for  wires.    (See  Protection  for  Wires.) 

Burglar  alarms   64 

Burrs  and  tins  in  fixtures 26  (6) 

Bus-bars 2  (6)  &  3  (e) 

Bushings  at  entrances  to  buildings 12  (g)  &  64  (e) 

Bushings  for  lamp  sockets 28  (/) 

Bushings  inside  of  buildings 14  (d) 

Cabinets,  cut-out  and  switch,  Use,  17  (6)  to  17  (d),  21  (c;  & 

Cabinets  for  rheostats  and  auto-starters,  where  required, 

8  (d) 
Cable,  Armored.    (See  Armored  Cable.) 

Car  houses 33 

ar  wiring  and  equipment 32 

-are  and  attendance 6 

Carrying  capacity  of  wires,  Table  of ....16 

iling  rosettes,  Use  of 21  (d) 

intral  stations 1  to  7 

Circuit-breakers,  how  high  maybe  set 21  (e) 

Circuit-breakers,  Installation  o'f 17  &  21 

Circuit  breakers,  where  required 8  (d)  &  9 

Compensator  coils  for  arc  lamps 30 


INDEX. 


NUMBER  ANI> 
SECTION. 

Compensator  coils  for  three-wire  systems.     (See  Re- 
active Coils.) 

Concealed  "knob  and  tube"  work 24  (q)  to  24  (it) 

Conductors.    (See  Wires.) 

Conduit  wiring ..24  (n)  to  24  (p) 

Conduits,  metal,  Installation  of 25 

Constant-current  systems 18  to  20 

Constant-potential  systems,  general  rules 21  to  23 

Converters.    (See  Transformers.) 

Cranes,  Electric 34  A 

Crossing  of  constant-potential  pole-lines,  over  5,000  volts 

12  A  (d) 

Cut-outs,  Installation  of 17  &21 

Cut-outs  must  protect  all  wires  of  the  circuit 17  (a) 

Cut-outs,  Number  of  lights  allowed  to  one. ..21  (d)  &  31  (a) 

Cut-outs,  where  required 1  (d),  2  (d),  8  (c),  21  (a),  21  (6; 

&  29  (a) 

Damp  places 14  (/),  17  (c),24  (i)  to  24  (&)  &  27  (6) 

Decorative  lighting  systems ...." 31 

Distance  between  conductors,  inside  work.. .18  (d),24  (h), 

24(j),24(r)  &35(e) 
Distance  between  conductors,  outside  work........ ...12  (ofl 

ranees  to  buildings :....12  (g)  &  64  i 

Dynamo  Rooms 


12  A  (c)  &  12  A  (d)  (2) 

Drip  loops  at  entrances  to  buildings 12  (g)  &  64  (d) 

1  to  7 


Economy  coils  for  arc  lamps 

Electric  gas  lighting 65 

Electric  heaters 

Electrolytic  corrosion  of  underground  metal  work.. .12  (n) 

Electro-magnetic  devices  for  switches  not  approved 

20  (c) 

Emergency  switches note  to  22  (a) 

Enclosed  arc  lamps 19  (c)  &  29  (c) 

Equalizers,  Installation  of * 

Extra-high  constant-potential  systems 38  &  39 

Fan  motors  hung  from  ceilings 8  (g) 

Feeders,  Railway 33  (/) 

Fished  wires 24  (c)  &  24  (*) 

Fittings,  List  of  approved.    (See  inside  of  front  cover.) 

Fixture  canopies 24  (w)  &  26  (a) 

Fixtures 26 

Fixture  Wiring 24  (v)  to  24  (y) 

Flexible  cord,  Use  of 28 

Flexible  tubing,  where  permitted 14  (d),  24  (s)  &  24  («) 

Foreign  currents,  Protection  against 64 

Formula  for  soldering  fluid 67 

Fuses,  Installation  of 1  (d),  17&21 


INDEX.  09 


NUMBER  AND 
SECTION, 

Gas  lighting,  Electric 65 

General  plan  of  arrangement  of  rules page  4 

General  suggestions  for  electric  work page  5 

Generators 1 

Ground  connections  for  lightning  arresters 5  (c) 

Ground  connections  for  low-potential  circuits 

13  A,  (c)  to  (g) 

Ground  detectors,  where  required 1  (a) 

Ground  plates,  Construction  of 13  A  (g} 

Ground  return  wires,  trolley  systems 12  (n) 

Grounded  trolley  circuits,  Light  and  power  from 34 

Grounding  dynamo  and  motor  frames ..l(c)  &8  )a) 

Grounding  interior  conduits  25  (/) 

Grounding  low-potential  circuits 13  A 

Grounding  sheaths  of  cables 12  (i) 

Grounds,  testing  for 7 

Guard  irons  or  wires,  Use  of 12  (d),  12  (wi),  12  A,  (d) 

Guard  strips,  inside  work,  where  required,  18  (e)  &24  (e) 

Heaters,  Electric 23 

High  constant  potential  systems 35  to  37 

Incandescent  lamps  as  resistances 4  (6)  &  29  (6) 

Incandescent  lamps  in  series : 20,  21  (d),  31  &  37 

Incandescent  lamps,  where  inflammable  gases  exist 

27  (a) 
Induction  coils.    (See  Reactive  coils.1) 

Inside  work 14  to  39 

Insulated  platforms,  at  high-potential  machines,  1  (c)  & 

8  (a) 

Insulating  joints,  when  required 26  (a) 

Insulation  of  future  canopies,  when  required 26  (a) 

Insulation  of  trolley  wires 12  (k) 

Insulation  resistance  of  completed  systems 66 

Insulator  spacing,  inside  work  24  (ft),  24  (j),  24  (r)  &  35  (c) 


Joint  pole  crossing,  high  pressure  line 12  A  (d),  2 

Joints,  in  conductors 12  (/)  &  14  (c) 

Junction  boxes,  conduit,  Installation  of..24  A  (/)  &  25  (g) 


Knob  and  Tube  work 24  (q)  to  24  (u] 

Knots  in  flexible  cord,  required  in  sockets  and  rosettes 

28(5-) 

Lumps.    (See  Arc  Lamps  and  Incandescent  Lamps.) 

Lighting  and  power  from  railway  wires... 34 

Lightning  arresters,  Installation  of 5 

Low  constant-potential  systems 24  to  34 

Lugs  for  terminal  connections,  when  required 14  (c) 


100  INDEX. 


NUMBER  AND 
SECTION. 

Mercury  vapor  lamps 29  A 

Motor  enclosures 8  (/) 

Motor  equipments,  550  volt,  voltage  allowed  at  genera- 
tor or  transformer note  before  24 

Motors        8 

Moulding,  metal,  Installation  of 25  A 

Moulding,  on  brick  walls 24  (I) 

Moulding,  Wires  in 24  (fc)  to  24  (m) 

Moving  picture  machines,  Construction  of 65  A 

Multiple-series  systems,  when  permitted 8  (e),  20  (c)  & 

29  (a) 

Oily  waste   6  (6) 

Open  wiring 24  (g)  to -24  (k) 

Outlet  boxes  or  plates,  Conduit,  when  required. ..24  A  (b) 

&  25  (d) 

Outline  Wiring 31  B 

Outside  work .12,  12  A,  13,  13  A  &  64 

Pendants  for  use  in  hazardous  places 28  (d) 

Pipe-hangers  for  incandescent  lamps 27  (a) 

Pole-lines,  Constant-potential,  over  5,000  volts 12  A 

Pole-lines,  High-pressure,  near  buildings 12  A  (e) 

Portable  lamps,  Installation  of 28  (d) 

Power,  transformer  and  switch  stations Ito7 

Protection  for  gas  outlet  pipes 26  (a) 

Protection  for  motor  equipments 8  (d) 

Protection  for  outlet  wires 24  («)  &  26  (a) 

Protection  for  wires  on  side  walls  or  columns 18  (e). 

•24  (e)  &  35  (d) 

Protective  devices  on  signal  circuits,  Construction  of 

64  (m) 
Protective  devices  on  signal  circuits,  Installation  of 

64  (g)  to  64  (J) 

Railway  power  plants 9 

Railway  wires.    (See  Trolley  Wires.) 

Receptacles.    (See  Sockets.) 

Resistance  boxes.    (See  Rheostats.) 

Resistances  used  with  constant-potential  arc  lamps,  29(6) 

Rheostats,  Installation  ot 4,  8  (c)  &  8  (d) 

Roof  wiring 12 

Rosettes,  Use  of 2l(rf) 

Running-boards,  Construction  of 18(e) 

Running-boards,  where  required 18  (e),24  (e)  &  35  (d) 

Screen  of  wires,  at  cross-over  in  high-pressure  pole  line* 

over  5,000  volts 12  A(rf)  (3) 

Series  arc  lamps Is* 

Series  incandescent  lamps 20  &  37 

' 


INDEX.  101 


NUMBER  AND 
SECTION. 

Series-multiple  systems,  when  permitted 8  (e)  &20  (c) 

Service  -wires,  Underground 15(a),  15(c),  15(d) 

Signaling  systems 64 

Sockets,  Installation  of 27 

Soldering  fluid,  Formula  for 67 

Soldering  stranded  wires 14  (c)  &  19  (d) 

Spark  arresters,  when  required 19  (c)  &  29  (c) 

Static  electricity,  due  $o  belt  friction 1  (c)  &  8  (a) 

Stations  and  dynamo  rooms I  to  7 

Stiff  pendants  for  incandescent  lamps 27  (a) 

Storage  battery  rooms 10 

Strips  for  protecting  inside  wires.    (See  Guard  Strips.) 

Switchboards 3 

Switches,  Electro-magnetic,  not  approved 20  (c) 

Switches,  Emergency note  to  22  (a) 

Switches,  Flush,  Installation  of 22  (d) 

Switches  for  constant-current  systems 18  (6) 

Switches  in  damp  places 17  (c) 

Switches,  Indicating,  when  required 8  (c),  23  (6) 

Switches,  Installation  of 17  &22 

Switches  must  disconnect  all  wires  of  circuit 17  (a) 


Switches,  Service 18  (6),22(a) 

Switches,  Single-pole,  when  permitted 8(c)  &22(c. 

Switches,  Snap,  when  preferred 22  (6) 


Switches,  Time 17  (d} 

Systems,  Constant-current   ...  ..18  to  20 

Systems,  Constant-potential,  general  rules 21to23 

Systems,  Extra-high  constant-potential 38&S9 

Systems,  High  constant-potential 35  to3' 

Systems,  Low  constant-potential. 24  to  34 

Systems,  Multiple- series 8  (e)  &  20  (c) 

Systems,  Series-multiple 8  (e)  and  20  (c) 

Systems,  Signaling 64 

Telegraph,  telephone  and  signaling  circuits 64 

Testing  for  grounds 7 

Testing  for  insulation  resistance  of  completed  systems, 

Theatre  wiring 31 A 

Three-pole  cross-over  for  high-pressure  line 12  A  (d-1) 

Tie  wires 12  (a)  &14  (6j 

Transformers,  grounding  of  secondaries 13  A(6i 

Transformers,  Installation  of,  inside 11  and  36 

Transformers,  Installation  of,  outside 13 

Transformer  stations Ito7 

Transmission  lines,  constant-potential,  over  5,000  volts 

12  A 

Trolley  circuits,  Grounded,  Light  and  power  from 34 

Trolley  wires 120')  to  12  (m) 

Tubes,  Insulating.    (See  Bushings.) 
Tubing,  Flexible.    (See  Flexible  Tubing.) 


102  INDEX. 


NUMBER  AHD 
SECTION. 

"Voltmeter,  Switchboard,  circuit  for  ...........................  2  (d) 

Waste,  oily  ......................................................................  6(6) 

Waterproof  construction  .............................  24  (f)  to  24  (k) 

Waterproof  pendants  .................................................  27  (6) 

Wire,  Netting  required  on  arc  lamps  ...........  19  (c)  &  29  (c) 

Wires,  Carrying  capacity  table  .......................................  16 

Wires,  Car  Work  ............................................................  32 

Wires,  Concealed  "knob  and  tube  "work.  ..24  (q)  to  24  (u) 
Wires,  Conduit  work  ................................  24  (n)  to  24  (p) 

Wires,  Constant-current  systems  ..................................  18 

Wires  in  stations  and  dynamo  rooms  ..........................  2  (e) 

Wires,  Spacing,  inside  work  .........  18  (d),24  (A),  24  (j),  24  (r) 

&  35  (c) 
Wires,  Spacing,  outside  work  ..................  12  (6),  12  A  (c)  & 

12  A  (d-2) 
Wires,  Extra-high  constant-potential  systems  ......  .38  &  39 

Wires,  Fished  ...............  ...................................  24  (c)&24  (s) 

Wires,  Fixture  work  .......................................  24(u)  to  24  (y) 

Wires,  Ground-  re  turn,  trolley  systems  .....................  12  (n) 

Wires,  High  constant-potential  systems  ........................  35 

Wires,  Inside  work,  general  rules  ..................................  14 

Wires,  Inside  work,  protection  in  crossing  wires  and 
pipes  ....................................................................  14  (e) 

Wires,  Low  constant-potential  systems  ..........................  24 

Wires,  Moulding  -work  ....................................  24  (I)  &24(w) 

Wires,  of  high-pressure  pole  lines  near  buildings,  12  A  (e) 
Wires  on  roofs  ....................................................................  12 

Wires,  Open  work,  damp  places  .....  14  (/)  &24  (i)  to  24  (K) 

Wires,  Openwork,  dry  places  .......................  24  (g)  &24  (h) 

Wires,  Outside  .............................................  12  and  12  A 

Wires,  Service  .........................................  12  (a),  12  (g),  64  (d) 

Wires,  Signal  ...................................................................  64 

Wires,  Stranded  ............................................  14  (c)  &  19  (d) 

Wires,  Tie      .......................................  12  (a)  and  14  (6) 

Wires,  Trolley,  installation  of  .....................  12  (j)  to  12  (TO) 

Wires,  Trolley,  Light  and  power  from  ...........................  34 

Wires,  Twin  when  permitted 


Wires,  Twin  when  pe 

Wires,  Underground  ..............................................  12  (i)  &  15 

Wires,  when  considered  exposed  to  moisture  .........  24  (./) 

vyiring,  General  suggestions  for  ..............................  Page  5 


Information  regarding  tests  mac 
these  rules  can  be  obtained  by  ad 
Underwriters'  Laboratories,  Chicago, 


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